Shortly after the United States entered World War I, the war department ordered the establishment of thirty-two divisional training camps-sixteen tent camps for the National Guard and sixteen camps with wooden buildings for the United States Army. Since the South Texas climate was favorable to uninterrupted training, and since Camp Wilson could easily be prepared to handle a division, San Antonio was chosen as one of the sites. Camp Wilson was five miles northeast of downtown San Antonio on the northeastern adjacent boundary of Fort Sam Houston. In May 1916 it became the mobilization point for the Texas National Guard during the Mexican border crisis. On July 15, 1917, after its selection as the training site for the Ninetieth (Texas-Oklahoma) Division of the army, it was renamed Camp Travis, in honor of Alamo hero William B. Travis. The camp was ready for occupancy on August 25, 1917. Additional land was subsequently acquired for vital training facilities, and numerous structures were erected by the soldier welfare agencies. Camp Travis comprised 18,290 acres, of which 5,730 were on the main campsite adjoining Fort Sam Houston.
The Ninetieth Division was organized at Camp Travis in September and October of 1917. The ranking officers, including Maj. Gen. Henry T. Allen, the division and camp commander, were regular army officers. The junior officers were primarily Texas and Oklahoma graduates of the officer-training camp at Camp Funston. The enlisted personnel consisted of Texas and Oklahoma draftees. Hispanics and Indians were intermixed with Caucasians in the new draft division, but Blacks were assigned to the camp depot brigade. By mid-October 1917 the Ninetieth Division numbered more than 31,000 officers and men. Equipment shortages, illness, and transfers to other commands interfered with training, however. At the time the division departed for Europe in June 1918 it was composed in considerable part of recent conscripts, many from states other than Texas and Oklahoma. During General Allen's absence in the late fall and winter of 1917–18 the division and camp were commanded successively by brigadier generals Joseph A. Gaston and William H. Johnston.
During the summer of 1918 Camp Travis served as an induction and replacement center, with an average strength in July of about 34,000 white and Black troops. In August and September the Eighteenth Division was formed of old and new units at the post under the command of Brig. Gen. George H. Estes. The Eighteenth was still in training when the war ended on November 11. On December 3 Camp Travis was named as a demobilization center. The facility was also designated a local recruiting station and a regional recruit depot in March 1919. Some 62,500 troops were discharged at Camp Travis in about eight months. The camp then became the home station of the Second Division. Its service as a separate entity was terminated, however, upon its absorption by Fort Sam Houston in 1922.