Adams-Onís Treaty Is Signed in Washington

Britain returned the Floridas to Spain in 1783, but American settlers later challenged Spanish authority in the west. Their rebellion in 1810 gave Washington an opportunity to claim territory it asserted belonged to the Louisiana Purchase. Napoleon's invasion of Spain had weakened the Spanish government. [2]

Luis de Onís and Secretary of State John Quincy Adams signed their treaty in Washington on 22 February 1819. Spain ceded East Florida and relinquished its claim to West Florida. The settlement also defined the western limit of the Louisiana Purchase: the United States recognized Spanish sovereignty over Texas, while Spain surrendered its claims to the Pacific Northwest. [2]

Negotiations had accelerated after Onís was received in Washington in 1815. American settlement and Spain’s wars had already weakened Spanish control. In 1818, Andrew Jackson invaded Florida during his campaign against Seminoles and people who had escaped slavery, capturing the Spanish posts at Pensacola and St. Marks. Adams defended Jackson’s actions and pressed Spain to control East Florida or surrender it. [2]

The treaty required ratification, completed in 1821. The United States assumed claims up to $5 million rather than making a purchase payment to Spain. Onís subsequently published his own account of the negotiations, explaining the choices he had made while defending Spain’s remaining territorial claims. [2] [3]

Related Diplomats

1. John Quincy Adams [2] [1]
2. Luis de Onís [1] [2] [3]

Related Reading

• Spain and the United States