This classical palace with Greek Revival detail is the last work of Frank Edbrooke, who designed it to harmonize with the state capitol, which it faces. In addition to completing the capitol, between 1880 and his death in 1921 Edbrooke's firm, F. E. Edbrooke Architect Co., designed a wide range of buildings, commercial and residential, that set the style of a blossoming city. The square, three-story Old State Museum building is sheathed in polished Colorado Yule marble on a Gunnison granite base. Four fluted marble columns with Ionic capitals support a shallow entrance portico. After the museum moved to 1300 Broadway in 1977, this building was restored as legislative offices. It retains its exquisite marble interior with golden oak and bronze trim.