The First Seminole War (c. 1816–1819) begins with General Andrew Jackson's excursions into West Florida and Spanish Florida against the Seminoles after the conclusion of the War of 1812.

The governments of Great Britain and Spain both express outrage over the "invasion".

However, Spain is unable to defend or control the territory, as several local uprisings and rebellions make clear.

The Spanish Crown agrees to cede Florida to the United States per the Adams–Onís Treaty of 1819, and the transfer takes place in 1821.

According to the Treaty of Moultrie Creek of 1823, the Seminoles are required to leave northern Florida and are confined to a large reservation in the center of the Florida peninsula.

The U.S. government enforces the treaty by building a series of forts and trading posts in the territory, mainly along the Gulf and Atlantic coasts.

The beginning and ending dates for the First Seminole War are not firmly established (it will not recognized as a war until much later).

The U.S. Army Infantry indicates that it lasted from 1814 until 1819.

The U.S. Navy Naval Historical Center gives dates of 1816-1818.

Another Army site dates the war as 1817-1818.

Finally, the unit history of the 1st Battalion, 5th Field Artillery describes the war as occurring solely in 1818.