Named after Brigadier General Thomas Sidney Jesup, a decorated veteran of the War of 1812, the US army erected Fort Jesup in 1822 along the Spanish Road, which linked Natchitoches to San Antonio and other Mexican cities. The fort replaced Fort Claiborne of 1804.
After the Louisiana Purchase of 1803, the western portions of Louisiana territory along the Red River were in a major disarray. Since 1763, Louisiana had been controlled by Spain. After Napoleon won the territory back in 1798, he promptly sold it the U.S. in 1803. No one, of course, asked the inhabitants what they wanted. Instead, a "neutral strip" of land between the Red and Sabine rivers was established by default, where gentleman's agreements were supposed to keep peace, but offered little in the way of an organized government. The people living there did not know to whom they owed allegiance... and some men took advantage of that. Some, like James Bowie, sold false land claims, while others may have tried to establish a New World kingdom, which Aaron Burr allegedly tried to do. The presence of the US army after the Adams-Onis Treaty of 1819 (which established the international borders between New Spain and the United States) was supposed to alleviate the doubts.
Like nearby Fort Towson in Indian Territory, Fort Jesup provided protection for native tribes and American settlers. Mostly, however, the troops engaged in road building, not combat. They built a road to Fort Smith, Arkansas and one towards Baton Rouge. During the Texas Revolution, American volunteers were mustered at Fort Jesup before entering Texas. The army regulars at Fort Jesup were also sent into Texas in 1845 to counter the Mexican army upon Texas statehood. Led by Zachary Taylor, one can argue that Fort Jesup started the Mexican American War (1846-1848).
The fort closed immediately after the Mexican American War. Its location was not of any great in importance thereafter, not even during the Civil War, as it remained unused. The federal government disbanded it completely in 1869.
Built in the Cane River Creole style of raised foundations, the fort gradually succumbed into ruins save for its kitchen, which was restored when the residents of nearby Many raised money to do so. By the 1950s, the Louisiana State Park department acquired the fort, which was also designated a National Historic Landmark.