Bodies of Water Study Guide

Overview

Bodies of Water is one of Jeopardy's most heavily tested geography topics, with over 3,400 clues spanning rivers, lakes, seas, bays, straits, and more. That volume means this topic appears in some form on nearly every other game — making it essential prep for any serious contestant. The 384 recurring answers break down into 96 Must-Know (8+ appearances), 90 Should-Know (4–7), and 198 Worth Knowing (2–3), so there's a long tail of answers, but the top tier alone covers a huge share of the clues you'll actually face.

Rivers dominate, accounting for nearly 1,000 clues and 108 distinct answers. The Nile (52 appearances), Amazon (46), Rhine (42), and Thames (41) lead the pack. Lakes contribute another 450+ clues headlined by Lake Geneva and Lake Victoria. Oceans & Seas round out the Big Three sub-areas. The show loves testing geographic relationships — which cities sit on which rivers, which countries border which seas, and which rivers flow into which bodies of water. City-to-river pairings (e.g., "Baghdad" → Tigris, "Florence" → Arno) are one of the most common clue formats.

Watch for high stumper rates on European rivers (Rhine 21%, Tagus 31%, Shannon 44%, Elbe 86%) and southern-hemisphere answers (Zambezi 36%, Lake Maracaibo 53%). These are the answers that trip up contestants on the show, and knowing them gives you an edge. This guide covers each sub-area in depth, starting with Rivers, then Lakes, Oceans & Seas, Bays & Gulfs, and Straits & Channels.

Rivers

Rivers are the heart of this topic — 108 recurring answers across 995 clues. Jeopardy loves rivers because they connect geography, history, and culture in a single answer. The most common clue format is "city X sits on this river" or "this river flows through country Y." Master the city-river pairings below and you'll nail the majority of river clues.

The Nile (52 appearances, 2% stumper)

The most-tested river in all of Jeopardy — and virtually a gimme (only 2% stumper rate). Key facts the show tests:

Source & course: Originates south of the equator (the farthest source is the Ruvironza River in Burundi). The White Nile and Blue Nile merge at Khartoum, Sudan. About 70% of the Nile's water comes from the Blue Nile, which originates in Ethiopia.
Delta: Enters the Mediterranean after splitting into the Rosetta and Damietta branches.
Aswan High Dam / Lake Nasser: Lake Nasser was created by impounding the Nile (completed 1970, filled by 1980s). The Sudanese portion is called Lake Nubia.
Cultural angles: "Tears of the goddess Isis" supposedly caused its annual flooding. The longest river in Africa (and contender for longest in the world).
Lake Victoria is the Nile's chief source — Jeopardy loves linking these two.

The Amazon (46 appearances, 7% stumper)

South America's giant. Slightly trickier than the Nile because clues go beyond the basics:

Origin of name: In 1542, Francisco de Orellana was attacked by female warriors while cruising down the river — hence "Amazon."
Scale: Carries more water than any other river. Drains parts of Brazil, Peru, Colombia, Ecuador, and others. Iquitos (Peru) and Macapá (Brazil) are key cities.
Wildlife: The pirarucu, one of the world's largest freshwater fish (nearly 10 feet), lives in the Amazon system.
The Rio Negro, a "black river" tributary, is virtually insect-free along its shores.

The Rhine (42 appearances, 21% stumper — watch out!)

Contestants miss this one often despite its frequency. Clues tend toward the specific:

Tributaries: The Ruhr, Moselle, and Neckar. Know these — they appear frequently.
Course: Rises in Switzerland, navigable for 500 miles from Basel to its mouth at the North Sea. Flows through Germany and the Netherlands.
Historical/cultural: Romans believed it was a shield protecting Gaul from Germanic tribes. The Lorelei rock is a famous landmark.
Why it stumps: Clues often mention tributaries or specific stretches rather than obvious features, and contestants confuse it with the Danube or Rhone.

The Thames (41 appearances, 2.5% stumper)

London's river and an easy get:

London Bridge: The famous bridge now at Lake Havasu, Arizona once spanned the Thames. This is a perennial Jeopardy angle.
Great Britain's rivers: The Severn is Britain's longest; the Thames is second. Know both.
Cultural: 1928 flood damaged the Tate Gallery storerooms. Henley-on-Thames hosts the famous rowing regatta.
Parliament, Big Ben, Westminster all sit along the Thames — visual clues reference this.

The Mississippi (39 appearances, 5% stumper)

America's river. Clues are widespread:

Source: Lake Itasca, Minnesota. Flows to the Gulf of Mexico.
Cities: Memphis, Minneapolis, St. Louis, New Orleans, Vicksburg. The Huey P. Long Bridge is a frequent reference.
Nicknames: "Father of Waters" and "Backbone of the Confederacy."
Borders: Forms Iowa's eastern border. Key tributaries include the Missouri, Ohio, and Arkansas rivers.
Paired with Missouri: "These 2 'stately' rivers are the longest in the U.S." is a classic clue.

The Missouri (36 appearances, 22% stumper — watch out!)

America's longest river (including the Mississippi system), but contestants struggle:

Course: Flows over 2,300 miles before entering the Mississippi just north of St. Louis.
Source: Near Three Forks, Montana. Great Falls, Montana is named for its nearby falls.
Fort Peck Dam created Montana's largest lake.
Why it stumps: Clues often describe the river's course or Montana landmarks without naming Missouri directly, and contestants guess the Mississippi instead.

The Danube (35 appearances, 0% stumper!)

A perfect record — no one misses the Danube. But know the details:

"Beautiful Blue Danube": Actually brown or sepia for most of its length.
Course: Rises in Germany's Black Forest, flows to the Black Sea. Passes through more countries than any other river (10), including Austria, Hungary, Serbia, and Romania.
Vienna & Budapest are the key city associations.
Europe's second-longest river (after the Volga).

The Seine (35 appearances, 3% stumper)

Paris's river and nearly a gimme:

Paris: Divides the city into Left Bank and Right Bank. Notre Dame sits on an island in the Seine.
Tributaries: The Marne joins the Seine near Paris — this comes up frequently, often with a WWI angle (two battles of the Marne).
Mouth: Reaches the English Channel at Le Havre.

The Volga (34 appearances, 15% stumper)

Europe's longest river, but the stumper rate means it's worth drilling:

Key facts: Flows into the Caspian Sea. At its mouth, the river is 92 feet below sea level.
Source: Valdai Hills.
Europe's longest — the Danube is second. This comparison appears regularly.
Moscow Canal links the Volga to Moscow.
Cultural: "The chief waterway of the Soviet Union." The Volga song is referenced in music clues.
Why it's tricky: Clues mentioning the Caspian Sea or "Europe's longest" sometimes stump contestants who think of the Danube.

The Ganges (33 appearances, 3% stumper)

India's sacred river:

Sacred to Hindus: Benares (Varanasi) is on its left bank — a holy city where Hindus bathe and scatter ashes.
Source: An ice cave in the Himalayas, over 10,000 feet above sea level, in Uttaranchal (Uttarakhand) state.
The Brahmaputra ("son of Brahma") joins the Ganges — both names appear in clues.

The Colorado (30 appearances, 20% stumper — watch out!)

Two versions appear in the database (as "the Colorado" and "the Colorado River" — 43 total):

Grand Canyon: The river carved it, and clues love this angle. "It's still working at deepening the Grand Canyon."
Dams: Hoover Dam → Lake Mead. Glen Canyon Dam → Lake Powell.
Tributaries: The Green and San Juan rivers join it in Utah.
Royal Gorge: The Arkansas River (not the Colorado) carved the Royal Gorge in Colorado — this is a common trick. "Over 1,000 feet deep, the Royal Gorge in this state was carved by the Arkansas River."
Why it stumps: Clues about dams and lakes in the Southwest often lead to the Colorado, but contestants sometimes blanch at the specifics.

The Rio Grande (23 appearances, 13% stumper)

The Mexico-U.S. border river:

Course: Rises in the Rocky Mountains, empties into the Gulf of Mexico at Brownsville, Texas.
Border: Forms the Texas-Mexico border. El Paso sits on it.
Conchos River: Mexico's longest river in Chihuahua state is a tributary.
1960s artificial riverbed: Built to prevent the river from shifting course.

The Potomac (21 appearances, 5% stumper)

Washington, D.C.'s river:

Mount Vernon: George Washington's estate overlooks the Potomac.
Arlington Memorial Bridge: Spans the Potomac, a frequent clue reference.
Great Falls: Large ships can't pass Washington, D.C. because of the falls.
Chesapeake Bay: The Potomac flows into it. The name is Algonquin for "where goods are brought in."

The Jordan (19 appearances, 6% stumper)

The Bible's river:

Most-mentioned river in the Bible. John the Baptist baptized Jesus here.
Course: Fed by rivers in Lebanon and Syria, rises on slopes of Mount Hermon. Flows from the Sea of Galilee to the Dead Sea.
Salt Lake City: There's also a Jordan River in Utah that empties into a very saline lake — Jeopardy has used this parallel.

The Ohio (18 appearances, 6% stumper)

The industrial heartland river:

Formation: The Allegheny + Monongahela = the Ohio, at Pittsburgh. This equation appears constantly.
Cities: Louisville, Cincinnati, Wheeling (WV), Evansville.
Kentucky border: Ironically, Kentucky has jurisdiction over the river, not Ohio.
"The Ohio River" also appears as a separate answer (8x) with similar clues about flowing from Pittsburgh to Cairo, Illinois.

The Mekong (18 appearances, 11% stumper)

Southeast Asia's great river:

Thailand-Laos border: This is the #1 clue angle.
Source: Discovered in 1994 — it's in Tibet.
Cities: Phnom Penh (Cambodia), Vientiane (Laos).
"Me Kong": A movie clue angle — "how a movie ape might identify himself."

Other Must-Know Rivers (8–16 appearances)

The Yangtze (16x, 0% stumper): China's and Asia's longest. Chang Jiang is its Chinese name. Nanjing and Shanghai are on it.
The St. Lawrence (14x, 0% stumper): "Mother of Canada." Seaway connects Montreal to Lake Ontario. Jacques Cartier explored it. Named for a saint martyred in Rome in the 3rd century.
The Euphrates (13x, 8% stumper): Joins the Tigris to form the Shatt al-Arab. Tabaqah Dam created Lake Assad. Fallujah and Raqqa are on it. "Tigris & Euphrates" as a pair (6x) — Mesopotamia, Armenian Plateau in Turkey.
The Tiber (13x, 17% stumper): Rome's river. Vatican City, Castel Sant'Angelo (Hadrian's mausoleum), Ponte Garibaldi. Watch out — contestants sometimes blank on Rome's river name.
The Tagus (13x, 31% stumper): Major stumper. Iberian Peninsula's longest river. Toledo (Spain) and Lisbon (Portugal). Called "Tajo" in Portuguese. The "Sea of Castile" is an artificial lake east of Madrid.
The Snake River (13x + 8x, 23% stumper): Idaho, Hells Canyon (deepest canyon in U.S.), joins the Columbia near Pasco, Washington. Lewis & Clark connection. Grand Teton National Park.
The Hudson (13x, 8% stumper): 315 miles, Troy → Albany → NYC. West Point. George Washington Bridge. Fulton's Clermont steamed up it in 1807.
The Red River (12x, 8% stumper): Texas-Oklahoma border, named for red sediment. There's ALSO a Red River through Hanoi, Vietnam — Jeopardy has used both in the same clue.
The Orinoco (11x, 18% stumper): Venezuela. Columbus sighted it in 1498. Angel Falls is on the Churun, a tributary. Ciudad Bolívar and Ciudad Guayana are on it.
The Congo (11x, 0% stumper): Brazzaville (Republic of Congo) and Kinshasa (DRC) face each other across it. 2nd longest in Africa, carries the most water after the Amazon.
The Arno (11x, 10% stumper): Florence (Ponte Vecchio!) and Pisa. The 1966 flood devastated Florence's art treasures. Tuscany's principal river.
The Zambezi (11x, 36% stumper): Big stumper. Victoria Falls. Zambia takes its name from it. Kariba Dam. Flows through 6 African countries — anagram clue: "MAZE BIZ."
The Po (10x, 20% stumper): Italy's longest river. Delta advancing into the Adriatic. Ticino tributary. Northern Italy's "main drain."
The Indus (9x, 22% stumper): Pakistan. Name from Sanskrit "Sindhu" meaning "river." Mohenjo-daro, cradle of civilization. Thar Desert stretches to its valley.
The Shannon (9x, 44% stumper): Huge stumper. Ireland's longest river. Limerick. Shannon Airport. Divides Ireland nearly in two. Ocean tides reach Limerick, 70 miles from the mouth.

Should-Know Rivers (4–7 appearances)

The Hudson River (7x, 29% stumper): George Washington Bridge, Fulton's Clermont, Tappan Zee Bridge.
The Elbe (7x, 86% stumper!): The toughest river. Dresden. Hamburg. Former East-West Germany border.
The Delaware (7x, 43% stumper): Philadelphia to New Jersey. Pennsylvania border with NY & NJ. Trenton. Washington's crossing reenactment at Titusville.
The Yellow River / Huang Ho (7x, 0%): China's 2nd longest. "China's Sorrow" from floods. Qinghai Province source.
The Rhone (7x, 57% stumper): Switzerland to France. Enters and exits Lake Geneva. Avignon's papal palace overlooks it.
The Tigris (6x, 33% stumper): Baghdad. Mosul. Name means "arrow" (faster than the Euphrates). Lake Hazar.
The Niagara River (6x, 67% stumper): Connects Lake Erie to Lake Ontario. Falls are halfway along.
The Mackenzie (6x, 0%): Canada's longest river. Great Slave Lake to Beaufort Sea. Named for an explorer.
The Loire (6x, 17%): France's famous château river. Called "Liger" by Romans. Nantes.
The Columbia River (6x, 50% stumper): Washington-Oregon border. Generates ~1/3 of U.S. hydroelectric power.
The Vistula (6x, 50% stumper): Poland's longest. Called "Wisła" in Polish. Warsaw.
The Dnieper (4x, 0%): Kyiv. Europe's 3rd largest. Rhymes with "deeper."
The Arkansas River (4x, 75% stumper): Fort Smith, Little Rock. Rises in Colorado Rockies. Royal Gorge.
The Wabash (4x, 25%): Indiana's state song river. Largest south-flowing Ohio tributary. Indiana-Illinois border.
The Charles (4x, 0%): Separates Cambridge from Boston. Harvard's Weld Boat House. Massachusetts's longest river entirely within the state.

Lakes

Lakes account for 454 clues across 57 recurring answers. The Great Lakes dominate American lake clues, while international lakes tend toward high-value squares. Know the "largest," "deepest," and "highest" superlatives — Jeopardy loves them.

Lake Geneva (30 appearances, 13% stumper)

The most-tested lake in all of Jeopardy:

Location: On the Swiss-French border. Montreux and Lausanne are on its shores.
Castle of Chillon: On the eastern shore, made famous by a Lord Byron poem.
The Rhone River: Enters at one end (near Montreux) and exits at the other (at Geneva). Enters milky from glacial clay, exits clear blue.
U.N. workers in Geneva overlook the lake with a view of the Alps.

Lake Victoria (26 appearances, 4% stumper)

Africa's largest lake:

Size: Largest freshwater lake in Africa. Second-largest freshwater lake in the world (after Lake Superior by surface area).
Countries: Tanzania, Kenya, and Uganda border it.
Nile source: Chief source of the Nile River. Jinja, Uganda is where the Nile exits the lake.
Named for: Queen Victoria.

Lake Michigan (26 appearances, 12% stumper)

Unique among Great Lakes: The only Great Lake entirely within the U.S.
Third largest of the Great Lakes.
Chicago connection: The Chicago River originally flowed INTO Lake Michigan; now it flows out (reversed in 1900). The Chicago Sanitary & Ship Canal connects it to the Mississippi system.
Rivers draining in: Muskegon, Kalamazoo, St. Joseph (from the east).
Depth: Reaches 923 feet. "Made Milwaukee famous."

The Great Salt Lake (25 appearances, 5% stumper)

No outlet: Streams flow in, but none flow out — hence the salinity.
Lake Bonneville: The Great Salt Lake is the largest remnant of prehistoric Lake Bonneville. The Bonneville Salt Flats are the former lakebed.
Saltier than any ocean. The largest lake in the western U.S.

Lake Baikal (22 appearances, 5% stumper)

The world's superlative lake:

Deepest in the world: About 5,300 feet deep (deepest point ~3,800 feet below sea level).
Location: Southeastern Siberia.
Unique wildlife: The Golomyanka fish is found only here. Also home to the world's only freshwater seal.
The Angara River is its only outlet.
Contains ~20% of Earth's surface fresh water.

Lake Ontario (17 appearances, 6% stumper)

Smallest of the Great Lakes — but almost as big as New Jersey.
Same name as the Canadian province.
Cities: Toronto and Oswego, New York.
Receives flow from Lake Superior (via the other Great Lakes) and feeds the St. Lawrence River.

Lake Superior (16 appearances, 0% stumper)

Largest of the Great Lakes and the largest freshwater lake by surface area in the world.
Westernmost and northernmost of the Great Lakes.
Erie is farthest south, Superior farthest north — a frequent comparison.
Thunder Bay, Pukaskwa National Park (Canada).

Lake Titicaca (15 appearances, 7% stumper)

World's highest navigable lake. In the Andes, on the Bolivia-Peru border.
Incan origin: According to tradition, the Incas originated on an island here.
Uros people: Pre-Incan people who still inhabit floating islands on the lake.

Lake Maracaibo (15 appearances, 53% stumper — watch out!)

Massive stumper despite 15 appearances:

Venezuela: It's technically an inlet of the Caribbean Sea (a "so-called lake").
Oil: Venezuela's petroleum wealth comes from here.
Named by explorer Alonso de Ojeda in 1499, who followed the coast and named the region "Venezuela" ("Little Venice").
Morandi Bridge: Italian engineer Riccardo Morandi bridged it using reinforced concrete.
Why it stumps: Contestants don't associate Venezuela with a major lake name.

Lake Huron (15 appearances, 33% stumper)

Second largest Great Lake by surface area, but longest shoreline of any of them.
Straits of Mackinac connect it to Lake Michigan.
Named for the Huron Indians.
Why it stumps: It's the "forgotten" Great Lake — contestants name the others first.

Lake Erie (15 appearances, 36% stumper)

Shallowest of the Great Lakes.
Southernmost Great Lake (Superior is northernmost).
Cities: Ashtabula, Toledo, Cleveland, Buffalo.
Cuyahoga, Detroit, and Sandusky rivers are tributaries.
Why it stumps: Clues about tributary rivers or port cities trip up contestants.

Lake Pontchartrain (14 appearances, 7% stumper)

Louisiana: Near New Orleans. Named for Louis XIV's marine minister.
Causeway: One of the world's longest over-water highways.
Lake Borgne connects it to the Gulf of Mexico.
Sieur d'Iberville renamed it from the native "Okwata" in 1699.

Lake Nasser (13 appearances, 39% stumper — watch out!)

Created by the Aswan High Dam on the Nile, completed 1970.
Named for Egyptian President Gamal Abdel Nasser.
The Sudanese portion is called Lake Nubia.
Took 13 years to reach near full capacity.

The Finger Lakes (13 appearances, 0% stumper)

New York State: Seneca, Cayuga, Owasco, Skaneateles, Otisco, and others — 11 total.
Wine region (though Jeopardy focuses on geography).
Glacially carved — long, narrow, finger-shaped.

Lake Mead (12 appearances, 18% stumper)

Created by Hoover Dam on the Colorado River.
15 miles east of Las Vegas. 110-mile-long artificial lake in Nevada.
Boulder Islands are a landmark.

Lake Champlain (12 appearances, 25% stumper)

Vermont-New York-Quebec border. Vermont's largest lake.
Discovered by Samuel de Champlain in 1609.
Richelieu River in Quebec issues from this lake.
Over half lies in Vermont, some in New York, northern tip in Quebec.

Lake Tahoe (11 appearances, 0% stumper)

California-Nevada border. In the Sierra Nevada.
Named by John C. Frémont (or noted by him).
Famous for its clarity and depth.

Other Must-Know Lakes (8–10 appearances)

Lake Tanganyika (10x, 30% stumper): Africa's deepest lake, world's 2nd deepest. Tanzania, DRC, Burundi, Zambia border it. Second-longest freshwater lake in the world.
The Caspian Sea (see Oceans & Seas) — technically the world's largest lake.
Lake Chad (8x, 25% stumper): Has been shrinking dramatically. Borders Chad, Nigeria, Niger, Cameroon.
Lake Powell (8x, 0%): Created by Glen Canyon Dam on the Colorado. In Utah/Arizona.
The Sea of Galilee (5x, see Oceans & Seas): Also called Lake Kinneret / Sea of Tiberias.

Oceans & Seas

With 396 clues across 39 answers, this sub-area is the third pillar of Bodies of Water. Clues tend to test which countries or features border a sea, or which rivers flow into it. The "which sea/ocean" format is common.

The Black Sea (26 appearances, 19% stumper)

Named because heavy winter fog makes the waters look dark.
Countries: Turkey, Russia, Ukraine, Romania, Bulgaria, Georgia.
Rivers flowing in: The Danube, Dnieper, and Dniester all empty into the Black Sea.
Connects to Mediterranean via the Bosphorus → Sea of Marmara → Dardanelles.

The Indian Ocean (26 appearances, 0% stumper)

Ancient name: Mare Indicum.
Third largest ocean. Bounded by Africa, Asia, and Australia.
Andaman Sea (Myanmar/Thailand) is a marginal sea of the Indian Ocean.
Christmas Island is in the Indian Ocean; Easter Island is in the Pacific — a common comparison.

The Caspian Sea (22 appearances, 18% stumper)

World's largest enclosed body of water (technically a lake).
The Volga flows into it — this is the #1 clue angle.
Countries: Russia, Iran, Kazakhstan, Turkmenistan, Azerbaijan.
Below sea level: The Volga enters the Caspian at 92 feet below sea level.

The Mediterranean (20 appearances, 5% stumper)

Sub-seas: The Adriatic and Ionian Seas are arms of the Mediterranean. The Aegean is another arm.
"Middle of the earth" — from Latin "medius" (middle) + "terra" (earth).
Rivers flowing in: Nile, Rhone, Ebro, Po.

The Red Sea (20 appearances, 0% stumper)

Biblical: Parted in Exodus for Moses.
Part of the Great Rift Valley.
Branches: Gulf of Suez (west) and Gulf of Aqaba (east) at its northern end.
Separates Africa from the Arabian Peninsula.

The Dead Sea (18 appearances, 11% stumper)

Lowest point on Earth's surface (~1,400 feet below sea level).
Arabic name: Sea of Lot (Bahr Lut).
The Jordan River flows into it with no outlet — hence extreme salinity.
Israel-Jordan border.
Not technically a sea — it's a hypersaline lake.

The North Sea (18 appearances, 0% stumper)

Rivers flowing in: Rhine, Weser, Elbe, Thames.
Borders: UK, Norway, Denmark, Germany, Netherlands, Belgium.
Oil: Major North Sea oil fields (though Jeopardy focuses on geography).

The Arctic Ocean (17 appearances, 24% stumper)

North Pole sits near its center.
Component seas: Barents, Beaufort, East Siberian, Kara, Laptev.
Smallest of the five oceans.
Why it stumps: Clues naming component seas (Barents, Kara) without saying "Arctic" trip people up.

The Bering Sea (15 appearances, 20% stumper)

Bristol Bay, Alaska, is an arm of the Bering Sea — rich salmon source.
Between Alaska and Russia. Named for Vitus Bering.
Connected to the Arctic Ocean via the Bering Strait.

The Baltic Sea (14 appearances, 31% stumper — watch out!)

Separates the Scandinavian Peninsula from continental Europe.
Countries: Denmark, Latvia, Sweden, Finland, Germany, Poland, Estonia, Lithuania, Russia.
Named for the Baltic people who lived on its shores in ancient times.
Gulf of Bothnia separates Sweden from Finland.
Why it stumps: Contestants confuse it with the North Sea or Black Sea.

The Adriatic (13 appearances, 8% stumper)

Between Italy and the Balkans. Named for ancient Roman port Adria/Hadria near Venice.
Po River delta advances into it.
An arm of the Mediterranean. The Ionian Sea lies at its southern end.

The Coral Sea (12 appearances, 33% stumper)

Named for reef formations. Off northeastern Australia.
Merges with the Solomon Sea (north) and Tasman Sea (south).
Battle of the Coral Sea (1942) — WWII naval battle.

The Caribbean Sea (12 appearances, 0% stumper)

Panama Canal made it one of the world's most traveled seas.
Windward Passage: Between Cuba and Haiti, a major shipping route.
Lake Maracaibo is technically an inlet of the Caribbean.

The Arabian Sea (10 appearances, 33% stumper — watch out!)

Touches Iran, Pakistan, and India — but NOT Saudi Arabia. This trick is a favorite.
Part of the Indian Ocean. The Gulf of Oman connects it to the Persian Gulf.

The Yellow Sea (10 appearances, 10% stumper)

Huang Hai in Chinese ("huang" = yellow, "hai" = sea).
Named for the yellow sediment carried by the Huang Ho (Yellow River).
Between China and the Korean Peninsula.

The Aegean (8 appearances, 0% stumper)

1,400+ islands, almost all Greek.
Part of the Mediterranean between Greece and Turkey.
The Saronic Gulf (near Athens/Piraeus) is an inlet.

Other Notable Seas

The Pacific/Atlantic Oceans (8–19x each): The Pacific was named by Magellan for its peacefulness. The Atlantic is the saltiest ocean and the second largest.
The Sea of Japan (5x, 20% stumper): Called "East Sea" by South Korea. Practically no tides.
The Sea of Galilee (5x, 0%): Also called Lake Kinneret and Sea of Tiberias. Biblical significance — Jesus walked on its waters.
The Tasman Sea (4x, 0%): Between Australia and New Zealand. Botany Bay is an inlet.

Bays & Gulfs

156 clues across 23 recurring answers. These tend to be high-value clues that test specific geographic knowledge.

The Bay of Bengal (20 appearances, 5% stumper)

The most-tested bay:

East of India, between India and Myanmar/Thailand.
The Ganges and Brahmaputra rivers flow into it.
Bangladesh sits at the head of the bay.
India's satellite launch failures in the 1980s "put it into this bay" — a classic clue.

The Bay of Biscay (18 appearances, 0% stumper)

Between France and Spain. Borders the Basque provinces.
Known for rough seas.
Easy to remember: Biscay = Basque country.

The Gulf of Mexico (17 appearances, 7% stumper)

Sigsbee Deep: Deepest point, about 200 miles southeast of Brownsville, Texas.
The Rio Grande and Mississippi empty into it.
Connected to the Caribbean Sea.

The Hudson Bay (14 appearances, 0% stumper)

Canada's huge bay. Foxe Channel connects it to the Arctic Ocean.
Named for Henry Hudson.
James Bay is its southern extension.

The Persian Gulf (11 appearances, 9% stumper)

Bahrain is an island nation in the Gulf of Bahrain within the larger Persian Gulf.
Bordered by Iran, Iraq, Kuwait, Saudi Arabia, Qatar, UAE, Oman.
Connected to the Arabian Sea via the Strait of Hormuz.

Puget Sound (10 appearances, 0% stumper)

Washington State. An inlet of the Pacific.
Navy shipyard at Bremerton.
Seattle, Tacoma, Olympia are on it.

Should-Know Bays & Gulfs (4–7 appearances)

The Bay of Fundy (7x, 0%): World's highest tides. Between New Brunswick and Nova Scotia. Tides reverse the flow of Canada's St. John River.
Manila Bay (7x, 14%): The Philippine capital is located on this bay. Dewey's naval victory in the Spanish-American War.
Chesapeake Bay (7x, 14%): Divides Maryland in two. Annapolis. Midshipmen.
The Gulf of Tonkin (6x, 0%): The Red River (from Hanoi) empties into it. Gulf of Tonkin Resolution (1964) escalated Vietnam War.
The Gulf Stream (5x, 20%): Not a gulf but a warm current. Carries tropical water, keeping N. European ports ice-free.
Biscayne Bay (5x, 20%): Cross it to reach Miami Beach from Miami.
The Gulf of California (4x, 0%): Between Baja California and mainland Mexico. Also called the Sea of Cortez.
Prudhoe Bay (4x, 25%): Alaska's North Slope. Trans-Alaska Pipeline terminus (with Valdez on the other end).

Straits & Channels

A smaller sub-area (47 clues, 11 answers), but these show up as mid-to-high-value clues.

The English Channel (8 appearances, 13% stumper)

Dover to Calais — the classic crossing.
Separates England from France.
The Seine empties into it (at Le Havre).
The Strait of Dover (5x, 80% stumper!) is the narrowest part. Churchill called it "the world's best tank trap." Massive stumper — know this one.

The Strait of Gibraltar (6 appearances, 0% stumper)

Tarifa, Spain and Tangier, Morocco are on opposite sides.
Connects the Mediterranean to the Atlantic.
Only 8.9 miles at its narrowest.

The Panama Canal (6 appearances, 17% stumper)

Limon Bay is the Atlantic-side approach.
Connects the Atlantic to the Pacific.
Uses locks (not a sea-level canal like Suez).

The Bering Strait (5 appearances, 0% stumper)

Separates Alaska from Russia. Only about 55 miles wide.
Average depth of only about 150 feet.
Named for Vitus Bering, who sailed through it.
Land bridge theory: Formed 10,000–15,000 years ago.

The Strait of Magellan (4 appearances, 25% stumper)

Southern tip of South America. Separates the mainland from Tierra del Fuego.
Punta Arenas, Chile is the chief port.
About 350 miles long.

The Dardanelles (4 appearances, 0% stumper)

Separates European and Asian Turkey. Turks call it the Strait of Çanakkale.
Connects the Aegean Sea to the Sea of Marmara.
Site of the Gallipoli campaign in WWI.