Gulf of Mexico

The Gulf of Mexico is an oceanic basin and a marginal sea of the Atlantic Ocean, largely enclosed by the North American continent. Its roughly oval shape spans about 810 nautical miles (1,500 kilometers) in width, with a basin area of approximately 1.6 million square kilometers. The floor is composed of sedimentary rocks and recent sediments. The gulf connects to the Atlantic Ocean through the narrow Straits of Florida, between the United States and Cuba, and to the Caribbean Sea via the Yucatán Channel, between Mexico and Cuba. These narrow connections result in very small tidal ranges. Moisture from the gulf influences weather across the United States, including severe storms in Tornado Alley.

The basin holds roughly 2.4 million cubic kilometers of water, and nearly half of it consists of shallow continental shelf waters. It is a major global center for offshore petroleum production, accounting for 14% of the total crude oil output of the United States.

The gulf’s name derives from the ethnonym Mexica, the Nahuatl-speaking people of the Valley of Mexico, commonly known as the Aztecs. In Aztec religion, the gulf was called Chalchiuhtlicueyecatl, or “house of Chalchiuhtlicue,” after the sea deity. Believing the sea and sky merged at the horizon, they referred to seas as ilhuicaatl, meaning “sky water,” distinguishing them from finite, landlocked bodies like lakes. The Maya civilization, which used the gulf as a major trade route, likely called it nahá, meaning “great water.”

European maps depicted the gulf by 1530 but left it unlabeled. Hernán Cortés called it the “Sea of the North” (Mar del Norte) in his dispatches, while other Spanish explorers used “Gulf of Florida” (Golfo de Florida) or “Gulf of Cortés” (Golfo de Cortés). A 1584 map by Abraham Ortelius also labeled it “Sea of the North” (Mare de Nort). Other early European names included “Gulf of St. Michael” (Sinus S. Michaelis), “Gulf of Yucatán” (Golfo de Iucatan), “Yucatán Sea” (Mare Iuchatanicum), “Great Antillean Gulf” (Sinus Magnus Antillarum), “Cathayan Sea” (Mare Cathaynum), and “Gulf of New Spain” (Golfo de Nueva España). At one point, New Spain encircled the gulf, with the Spanish Main extending into what later became Mexico and the southeastern United States.

The name “Gulf of Mexico” (golfo de México; golphe du Mexique) first appeared on a world map in 1550 and in a historical account in 1552. Europeans named it after Mexico, land of the Mexica, because mariners needed to cross the gulf to reach that destination. This name became the most common by the mid-17th century, when the gulf was still considered a Spanish sea. French Jesuits used it as early as 1672. In the 18th century, Spanish admiralty charts labeled it “Mexican Cove” or “Mexican Sound” (Ensenada Mexicana or Seno Mexicano). Until the Republic of Texas broke away from Mexico in 1836, Mexico’s coastal boundary extended eastward along the gulf to present-day Louisiana.

In other languages of Mexico, the gulf is known as Ayollohco Mexihco in Nahuatl, u golfoil México in Yucatec Maya, and golfo yu’un México in Tzotzil. The International Hydrographic Organization officially recognizes “Gulf of Mexico” and counts all three adjacent countries as member states, though no formal protocol governs naming international waters.

In January 2025, a U.S. executive order directed federal agencies to rename the portion of the gulf within U.S. territorial waters as the “Gulf of America.” Some major online map services and U.S.-based media outlets adopted the change for U.S. users, but it sparked controversy, with Mexican president Claudia Sheinbaum and others objecting. A February 2025 Marquette University poll of 1,018 U.S. respondents found 71% opposed the renaming and 29% supported it.

The southeast limit of the gulf, as defined by the International Hydrographic Organization, runs from Cape Catoche Light in Mexico to Cape San Antonio in Cuba, then north along the meridian of 83°W to the latitude of the south point of the Dry Tortugas, east along that parallel to Rebecca Shoal, and through the Florida Keys to the mainland at the eastern end of Florida Bay, with all narrow waters between the Dry Tortugas and the mainland considered within the gulf.

The U.S. Gulf Coast region, comprising parts of five states, had a total population of 15.8 million in 2016. The six Mexican states bordering the gulf had 19.1 million people. The three westernmost provinces of Cuba, including Havana, had 3,211,000. Historically, industrial activity has supported significant temporary populations; by 1975, 400 offshore drilling rigs in the gulf hosted such a population.