Mobile Bay is a shallow inlet of the Gulf of Mexico, lying within the state of Alabama in the United States. Its mouth is formed by the Fort Morgan Peninsula on the eastern side and Dauphin Island, a barrier island on the western side. The Mobile River and Tensaw River empty into the northern end of the bay, making it an estuary. Several smaller rivers also empty into the bay: Dog River, Deer River, and Fowl River on the western side of the bay, and Fish River on the eastern side. Mobile Bay is the fourth-largest estuary in the United States with a discharge of 62,000 cubic feet (1,800 m3) of water per second. Annually, and often several times during the summer months, the fish and crustaceans will swarm the shallow coastline and shore of the bay. This event, appropriately named a jubilee, draws a large crowd because of the abundance of fresh, easily caught seafood.

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.