Ringgold Barracks, later known as Fort Ringgold, functioned as a United States Army post guarding the lower Rio Grande border near Rio Grande City. Established in 1848 in the aftermath of the Mexican War, it was the southernmost post in a chain of forts built to secure the new international boundary and protect area residents from raids and unrest on both sides of the river. Troops stationed there patrolled against smugglers, cattle rustlers, and cross-border incursions, and the post played an active role during periods of border violence, including cooperation with Texas Rangers against Juan Cortina's forces around 1860. Robert E. Lee was posted there in 1860 while investigating border conflict, and the house he occupied still stands. Beyond its military patrols, the garrison contributed to the local economy and infrastructure, at one point hosting the area's first telegraph office, and its presence helped stabilize and grow the surrounding community of Rio Grande City. The Army maintained a presence at the post through the early twentieth century, including use during the Mexican Revolution era, before the post was declared surplus and disposed of in 1944. In 1949 the Rio Grande City Consolidated Independent School District acquired the property, and several original nineteenth-century buildings still stand on the grounds today, now serving school functions. Historical markers throughout the campus interpret the fort's role in border defense, and the site remains one of the best-preserved former border garrisons in South Texas.