West Florida Controversy, conflict between Spain and the United States concerning possession of Florida. By the Treaty of Paris of 1763, Britain received Florida from Spain, and from France that portion of Louisiana lying between the Mississippi and Perdido rivers (exclusive of New Orleans). The British organized this territory into the provinces of East Florida (most of the present state of Florida) and West Florida (the strip on the Gulf Coast formed by parts of the present states of Florida, Alabama, Mississippi, and Louisiana). The Apalachicola River was the boundary. In 1764 they arbitrarily moved the northern boundary of West Florida from 31°N to a line running from the mouth of the Yazoo River east to the Chattahoochee River (32°28′N). After the American Revolution the British ceded Florida back to Spain, but without clear definition of its boundaries. A controversy immediately developed over the northern boundary of West Florida. The Spanish demanded the 1764 line; the United States insisted on the old line of 31°N. The issue was settled by Pinckney's Treaty (1795), in which Spain recognized the American claim. With the transfer of Louisiana from Spain to France and its subsequent purchase (1803) by the United States, another dispute over West Florida's boundaries developed. Based on the treaty of cession with France, which did not specify the boundaries of the Louisiana Purchase, the United States claimed that part of West Florida (between the Perdido and the Mississippi rivers) that had been part of Louisiana before 1763. The Spanish insisted that Louisiana, as held and administered by them, had not included this area. Lengthy and inconclusive negotiations ensued. At the same time American settlers moved into the area and resisted Spanish control. In 1810, after a revolt against Spanish rule in West Florida, President Madison ordered United States occupation of the disputed area, which was incorporated into the Territory of Orleans (which became the state of Louisiana in 1812) and the Mississippi Territory. Spain refused to recognize the American occupation, and American expansionists contemplated taking East Florida. The issue was finally settled in 1819, when, by the Adams-Onís Treaty between U.S. Secretary of State John Quincy Adams and the Spanish minister Luis de Onís, Spain renounced its claims to West Florida and also ceded East Florida to the United States.

See I. J. Cox, The West Florida Controversy, 1798–1813 (1918, repr. 1967).