Fort Brown was a military post of the United States Army in Cameron County, Texas used during the later half of the 19th century and the early part of the 20th century.The site was constructed in April 1846 by General Zachary Taylor and his U.S. Army of Occupation and was intended to bolster U.S. assertions that the Rio Grande was the southern boundary of the United States, but its presence only heightened tensions with Mexico. Mexico disputed the U.S. claim to the Rio Grande and assembled an army to confront the troops in the U.S. fort.

The siege of Fort Brown prompted the first major battles of the U.S.-Mexican War, but that war also shaped the history of the fort. The conflict officially established the Rio Grande as the boundary between the United States and Mexico, and Fort Brown remained an important post on that border until after World War II. The original earthworks, however, were abandoned shortly after the siege of May 1846 and were never again used.	