Battles & Campaigns · 1819
Adams–Onís Treaty
Washington, D.C., USA
What happened
The United States and Spain disagreed over Florida and their borders in the west. In Washington, Spain agreed to hand East and West Florida to the United States. In return the US gave up its claims to Texas, and the two set a border running all the way to the Pacific Ocean.
Why it matters
Why it matters: It gave the United States its first border stretching across the continent. Spain kept Texas as a buffer between its colonies and US lands.
What came next
Spain delayed ratifying until October 1820, and the treaty took effect on 22 February 1821. Months later Spain recognised Mexican independence.
Did you know?
Part of the border was drawn along the Arkansas River, whose source was not found until the 1840s.
Timeline
- 22 February 1819Treaty signed.
- 24 February 1819US Senate approves it.
- October 1820Spain ratifies.
- 22 February 1821The treaty takes effect.