In the summer of 1851, soldiers established the first Fort Union at the foot of the mesa, about a mile away, quickly erecting buildings of logs and uncured, rough-sawn lumber to create a federal presence and protect local residents and travelers on the Santa Fe Trail from raids by the Comanches, Kiowas, Apaches, and Mountain Utes. The small post served as headquarters for the entire Ninth Military District, later renamed the Military Department of New Mexico. Its log buildings leaked and deteriorated quickly, and when the time came to build the third Fort Union, the Army chose more durable adobe instead of local lumber. The first fort had been placed near the mesa to shelter barracks, quarters, shops, and supply warehouses from the area's nearly constant winds.