The town was named for Judge Marshall Silverthorn who served as the judge of the miners' court in Breckenridge. The judge first came to town as a prospector and claimed a section of the Blue River in 1881. After patenting his claim in April 1882, he was disappointed to find the gold to be sparse and the claim a poor bet. The land passed to his daughters on his death in 1887 and was then sold several times to various mining companies. In 1953 Clayton Hill bought the property and subdivided it for homes and stores. Silverthorne served as a makeshift camp for workers during the construction of the Dillon Reservoir from 1961–1963, and later as a stop along Interstate 70. It was eventually incorporated on April 5, 1967. The city has expanded several times since incorporation by annexation.