Miguel Hidalgo y Costilla declared Mexico's independence from Spain on September 16, 1810. In 1819, the United States ceded its claim to the land south and west of the Arkansas River to Spain with the Adams-Onís Treaty, at the same time purchasing Florida. Mexico finally won its independence with the Treaty of Córdoba signed on August 24, 1821, and assumed the territorial claims of Spain. Although Mexican traders ventured north, settlers stayed south of the 37th parallel north until the United States signed a peace treaty with the Ute Nation in 1850.