The Bay of Campeche, or Campeche Sound, is a bight in the southern area of the Gulf of Mexico, forming the north side of the Isthmus of Tehuantepec. It is surrounded on three sides by the Mexican states of Campeche, Tabasco and Veracruz. The area of the bay is 6,000 square miles (16,000 km2) and maximum depth of the bay is approximately 180 feet (55 m). It was named by Francisco Hernández de Córdoba and Antón de Alaminos during their expedition in 1517.

The Gulf of Mexico is an ocean basin and a marginal sea of the Atlantic Ocean, mostly surrounded by the North American continent. It is bounded on the northeast, north and northwest by the Gulf Coast of the United States; on the southwest and south by the Mexican states of Tamaulipas, Veracruz, Tabasco, Campeche, Yucatán, and Quintana Roo; and on the southeast by Cuba. The Southern U.S. states of Texas, Louisiana, Mississippi, Alabama, and Florida, which border the gulf on the north, are often referred to as the "Third Coast" of the United States.