[1] In 1846, Captain Joseph K. Mansfield[3]: 40  directed the construction of a star-shaped earthwork for 800 men called "Fort Texas" on the northern side of the Rio Grande "by the order from General [Zachary] Taylor to command the city of Matamoros" south of the river.

During the Siege of Fort Texas, two Americans were killed, including Major Jacob Brown and George Oakes Stevens (of Vermont) of the 2nd Dragoons.

While in command at the fort, Major Samuel P. Heintzelman coordinated with John Salmon Ford in the Cortina Troubles, culminating in the Battle of Rio Grande City in 1859.

This Union occupation ended in 1864, when Confederate forces under General James E. Slaughter and Colonel Ford took control of the area.

In 1882, Dr. William Crawford Gorgas was assigned to the hospital at Fort Brown during the height of a yellow fever outbreak.

The Army investigated the matter and concluded that the Black soldiers were guilty although their supervising officers supported them and said that they had been at the fort.

On April 20, 1915, U.S. Signal Corps Officers Byron Q. Jones and Thomas Millings flew a Martin T over the fort to spot movements of the Mexican revolutionary leader Francisco "Pancho" Villa.

After the Japanese attack on Pearl Harbor, the division served with distinction, dismounted, in the China Burma India Theater, where a member of the unit from Fort Brown earned the theater's only Medal of Honor (awarded to Jack L. Knight, commanding F Troop).

[8] The Consolidated Appropriations Act, 2023 authorized the addition of Fort Brown (166 acres) to Palo Alto Battlefield National Historical Park.