Following the Civil War, state officials reorganized the Wisconsin Militia and in 1879 renamed it the Wisconsin National Guard. Adjutant General Chandler P. Chapman of Madison, a veteran of the famed Iron Brigade, purchased 440 acres near the Village of Camp Douglas, which was used for rifle practice beginning in 1888. Chapman transferred the land to the State shortly thereafter. The original tract was enlarged and became known as the Wisconsin Military Reservation. National Guard training camps were conducted at the Military Reservation, and within a few years Wisconsin troops had earned a national reputation for marksmanship and other soldiering skills. Four regiments of the Guard were rapidly mobilized for duty at the outbreak of the Spanish-American War (1898), demonstrating the efficiency of the state's training program. Guard units mobilized on the grounds during both World Wars.
In 1927 the Wisconsin Military Reservation was renamed Camp Williams in honor of Lt. Col. Charles R. Williams, the training camp's Quartermaster who is buried on the site. Hundreds of thousands of Guard members have been trained on the installation since 1900. In 1957 the state legislature ordered the portion of the Reservation used by the Air National Guard to be named Volk Field in honor of Lt. Jerome A. Volk, the first Wisconsin fighter pilot killed in action during the Korean Conflict.