The Gulf of Mexico is a partially landlocked ocean basin

Oceanic basin

Hydrologically, an oceanic basin may be anywhere on Earth that is covered by seawater, but geologically ocean basins are large geologic basins that are below sea level...

 largely surrounded by the North America

North America

North America is a continent wholly within the Northern Hemisphere and almost wholly within the Western Hemisphere. It is also considered a northern subcontinent of the Americas...

n continent and the island of Cuba

Cuba

The Republic of Cuba is an island nation in the Caribbean. The nation of Cuba consists of the main island of Cuba, the Isla de la Juventud, and several archipelagos. Havana is the largest city in Cuba and the country's capital. Santiago de Cuba is the second largest city...

. It is bounded on the northeast, north and northwest by the Gulf Coast of the United States

Gulf Coast of the United States

The Gulf Coast of the United States, sometimes referred to as the Gulf South, South Coast, or 3rd Coast, comprises the coasts of American states that are on the Gulf of Mexico, which includes Texas, Louisiana, Mississippi, Alabama, and Florida and are known as the Gulf States...

, on the southwest and south by Mexico

Mexico

The United Mexican States , commonly known as Mexico , is a federal constitutional republic in North America. It is bordered on the north by the United States; on the south and west by the Pacific Ocean; on the southeast by Guatemala, Belize, and the Caribbean Sea; and on the east by the Gulf of...

, and on the southeast by Cuba. In Texas and Louisiana it is often called the "Third Coast," in comparison with the U.S. Atlantic and Pacific coasts. The shape of its basin is roughly oval and is approximately 810 nautical miles (1,500.1 km) wide and filled with sedimentary rocks and debris.