The town was named for Judge Marshall Silverthorn who served as the judge of the miner's 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.