Established March 27, 1849, by Capt. Sidney Burbank with Companies A, B, and F, First U.S. Infantry. Name honors Col. James Duncan, a hero of the Mexican War.
Fort served as a frontier outpost near trail of California emigrants; base of operations against hostile Lipan Apache Indians. In 1851 it became the headquarters of the First Infantry. By 1856 garrison included units of mounted rifles and first artillery. Abandoned May 1859, post was regarrisoned in March 1860 because of border assaults by Juan N. Cortina, desperado of the area. At outbreak of the Civil War, 1861, fort was again abandoned, only to be occupied later as "Rio Grande Station", by Confederate forces.
In 1868 Fort Duncan was regarrisoned by the 9th Infantry and headquarters company of 41st Infantry, under Col. William R. Shafter. Seminole-Negro Scouts, organized here Aug. 16, 1870, played a large part in ridding Western Texas of Indians. After 1883, post declined in importance; known as Camp Eagle Pass, it was abandoned about 1900. Mexican border troubles in 1916 again brought reoccupation; its use as a training camp continued during World War I.
In 1938 the fort property was purchased by City of Eagle Pass, for use as park and recreation area.