The Mobile District was an administrative region of the Spanish territory of West Florida, which became part of the independent Republic of West Florida on September 23, 1810. The region was bounded in the north by the 31st parallel, in the south by the Gulf of Mexico, in the east by the Perdido River, and in the west by the Pearl River. The territory was annexed by the United States in 1812 and currently forms parts of the states of Mississippi and Alabama.