During the early 19th century it played a central role in a series of rotating boundary changes and disputes among France, Spain, Great Britain, and the United States.

It flows generally east-southeast in a winding course and enters the north end of Perdido Bay on the Gulf of Mexico, approximately 10 miles (16 km) west of Pensacola.

In 1800, as part of the Treaty of San Ildefonso, Spain returned the Louisiana colony to France, retaining control of the lands east of the Mississippi River (except New Orleans).

The Gulf coast south of 31 degrees latitude, between the Mississippi and Perdido rivers, remained disputed between the two nations.

Ninety days later, U.S. military forces entered its capital (St. Francisville, Louisiana) and effectively annexed the short-lived nation.