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50 free Gulf of Mexico trivia questions with answers — geography quiz, new questions added Aug 2026.
The Gulf of Mexico is a 1.6-million-square-kilometre bowl of warm water that makes the Gulf Stream, feeds Tornado Alley and produces a seventh of America's crude oil. This quiz starts with the basics: which ocean it belongs to, which straits connect it to the Atlantic and the Caribbean, how many US and Mexican states touch it, and where its deepest point lies. Then it goes below the surface to the Louann Salt, the brine pools nicknamed the 'Jacuzzi of Despair', the clockwise Loop Current and the eddies it sheds. The history section runs from Olmec river cities and Maya mahogany canoes through Cortés calling it the Sea of the North, the 1517 discovery of Yucatán, the Padre Island treasure wreck, the Narváez expedition and d'Iberville landing at Biloxi. Modern questions cover the U-boat sunk off the Mississippi in 1942, the hypoxic dead zone, the Ixtoc I and Deepwater Horizon spills, Hurricane Katrina, the buried Chicxulub crater and the 2025 'Gulf of America' renaming row. Easy questions suit anyone who has looked at a map of North America; the expert tier asks about Sverdrups and salt tectonics. Every answer was checked against Wikipedia's articles on the Gulf and its major events, and the supporting sentence is attached to each question.
30 of 50 questions with answers and explanations. Play the quiz
Q 01The Gulf of Mexico is a marginal sea of which ocean?
The Atlantic
Its connections to the open ocean are so narrow that its tides are tiny.
Q 02Which island nation bounds the Gulf on its southeast?
Cuba
Its three westernmost provinces, including Havana, have a combined population of about 3.2 million.
Q 03The Gulf connects to the open ocean through which strait?
The Straits of Florida
The strait is only about 900 metres deep at most, so exchange with the ocean happens in the upper layers.
Q 04Water enters the Gulf from the Caribbean Sea through which passage?
The Yucatán Channel
The current through it can reach 120 centimetres per second and fills the channel to a depth of about 800 metres.
Q 05Moisture from the Gulf is a primary factor in severe weather in which famously storm-prone US region?
Tornado Alley
Dry air from the Rockies collides with the Gulf moisture to build the supercells that spawn the region's violent twisters.
Q 06Roughly how large is the Gulf of Mexico basin?
1.6 million square kilometres
Almost half of that area is shallow continental shelf, and the whole basin holds about 2.4 million cubic kilometres of water.
Q 07In the early 2020s, the Gulf accounted for roughly what share of US crude oil production?
14%
By 1975 there were 400 rigs hosting more than 10,000 workers on any given day, though automation later thinned the offshore workforce.
Q 08The Aztecs named the Gulf the 'House of Chalchiuhtlicue', after their deity of what?
The seas
They believed sea and sky merged at the horizon and called the seas ilhuicaatl, 'sky water'.
Q 09The Maya, who used the Gulf as a major trade route, likely called it nahá, meaning what?
Great water
Maya traders paddled long canoes carved from single mahogany trunks and navigated by coastal landmarks and lookout towers.
Q 10What did Hernán Cortés call the Gulf in his dispatches?
Sea of the North
Other Spaniards preferred 'Gulf of Florida', and Abraham Ortelius' 1584 map still used the same northern label.
Q 11In which year did the name 'Gulf of Mexico' first appear on a world map?
1550
Europeans named it after the land of the Mexica because mariners had to cross it to get there; it became the usual name by the mid-17th century.
Q 12A January 2025 US executive order directed agencies to adopt which name for the gulf bounded by the United States?
Gulf of America
Mexican president Claudia Sheinbaum objected, and a Marquette University poll found 71% of Americans opposed the change.
Q 13Which body officially recognises the name Gulf of Mexico and includes all three bordering countries?
The International Hydrographic Organization
Q 21The Orca Basin brine pool, formed by several merged salt domes, reaches what salinity at depth?
300 ppt
Normal seawater averages 35 ppt; the pool covers about 400 square kilometres and has zero dissolved oxygen.
Q 22The Loop Current that dominates the Gulf circulates in which direction?
Clockwise
It is as strong as the current it feeds, up to 300 kilometres across, and sheds warm rings that drift west at about 0.2 knots.
Q 23The Florida Current, exiting through the Florida Straits, becomes which famous ocean current?
The Gulf Stream
The whole system is part of the North Atlantic Gyre along with the North Atlantic, Canary and North Equatorial currents.
There is no formal protocol for naming international waters, so its standardisation is only for certain purposes.
Q 14How many US states border the Gulf of Mexico?
Five
Florida, Alabama, Mississippi, Louisiana and Texas; in 2016 the region held 15.8 million people.
Q 15How many Mexican states have a Gulf coastline?
Six
Together they hold 19.1 million people, more than the US Gulf Coast region.
Q 16The Gulf of Mexico took shape roughly how long ago as a result of plate tectonics?
300 million years
Before the late Triassic the area was dry land in the middle of Pangaea; rifting later flooded it into an enclosed sea.
Q 17Which Jurassic evaporite formation under the northern Gulf produces its brine pools and diapirs?
The Louann Salt
Under the pressure of overlying sediment the salt flows and rises, a process called salt tectonics.
Q 18The Gulf's greatest depth is found in which feature?
The Sigsbee Deep
The Gulf floor is 41% continental slope, 32% shelf and only 24% abyssal plain.
Q 19How deep is the Gulf of Mexico at its deepest point?
12,467 feet
That is about 3,800 metres, deep enough that its central floor is true abyssal plain.
Q 20A Gulf-floor brine pool found in 2014 was nicknamed the 'Jacuzzi of Despair' because it is what?
Warmer than the surrounding water
At 18 °C against 4 °C around it, and several times saltier, it can only support bacteria, symbiotic mussels, tube worms and some shrimp.
Q 24About 40% of the water flowing into the Gulf from the Caribbean originally comes from where?
The South Atlantic
That component is warmer and fresher, and a deeper layer of the current is Antarctic Intermediate Water.
Q 25Which civilisation built cities such as San Lorenzo Tenochtitlán on the Gulf's southern coast around 1200-400 BC?
The Olmec
They relied on fishing, turtles and the floodplain while gradually farming more maize.
Q 26Who discovered the Yucatán Peninsula for Spain in 1517?
Francisco Hernández de Córdoba
He died the same year of wounds and thirst from the voyage, bitter that Grijalva had been given the follow-up expedition.
Q 27A Spanish treasure ship was wrecked on which part of the Texas coast, prompting a famous salvage effort?
Padre Island
The loss helped convince Spain to plant a settlement on the northern Gulf coast to protect shipping and rescue castaways.
Q 28The expedition of Tristán de Luna y Arellano landed in 1559 at which bay?
Pensacola Bay
It came out of a plan to establish a northern Gulf settlement after a string of ship disasters.
Q 29In February 1699 d'Iberville went ashore with his teenage brother at what is now which Mississippi city?
Biloxi
The brother, Jean-Baptiste Le Moyne de Bienville, was left as second in command and later founded New Orleans.
Q 30The French fort at the mouth of the Mississippi was named La Balize, which means what?
Seamark
The first permanent settlement, Fort Maurepas, is now Ocean Springs, Mississippi.