Riverside served as the summer residence of Margaret Daly, widow of copper magnate Marcus Daly, from its completion in 1910 until her death there in 1941. Marcus Daly had begun buying Bitterroot Valley land in 1887 and eventually owned 28,000 acres. After his death in 1900, Margaret Daly had Riverside constructed and managed local family properties and the family syndicate that oversaw Daly interests. The house is a unique Montana example of early-twentieth-century revival styles used by successful capitalists to display their wealth. Because the Panic of 1893 destroyed many mining-based fortunes in Montana, and out-of-state investors financed later mining ventures, grand homes were largely a thing of Montana’s past by the time Riverside was built. Missoula architect A. J. Gibson designed the house in the Georgian Revival style, and although comparatively restrained for mansions of its period, it features a monumental classical portico, a symmetrical façade, a hipped roof, and a balustrated roof deck. Today, the appearance of its interior decoration and professionally landscaped grounds remains virtually unchanged from 1910.