The Mills Building served as the junta headquarters of Constitucionalistas in 1913. The junta, called the “Mills Junta” by the El Paso press, included Villa supporters Silvestre Terrazas and Aureliano González, brother of assassinated Chihuahua Governor Abraham González. The Huertista federal forces threatened to blow up the Mills Building if the U.S. government officially recognized the Villistas and granted them permission to import arms into Mexico. One Huerta officer told the El Paso Herald on August 9, 1913, “The Mills building, standing out prominently as it does, will make an admirable target.”
Construction of the Mills Building was begun in the spring of 1910. By 1915, the twelve-story Mills Building, designed by Trost & Trost architects, was the largest reinforced concrete structure in the U.S.