Situated across from the Washington State Building, the Montana State Building stood on the south side of the Panama-California Exposition's Via de los Estados. The building was designed in a Spanish-Mission style, and borrowed design elements from exposition structures located along El Prado. A central terra-cotta tile-roofed hall, with decorative end-gables, was flanked by flat-roofed wings at either side, each featuring a pergola-covered side entrance. The arched main portal borrowed its surrounding ornamentation from the arcade entrance pavilions, located along El Prado; while the parapet ornamentation, placed on the structure's two flanking wings, was borrowed from the front arcade of the Southern California Counties Building. The interior of the building housed the many exhibits assembled by the State of Montana.