St. Elmo is a ghost town in Chaffee County, Colorado, United States. Founded in 1880, St. Elmo lies in the heart of the Sawatch Range, 20 miles (32 km) southwest of Buena Vista and sits at an elevation of 9,961 feet (3,036 m). Nearly 2,000 people settled in this town when mining for gold and silver started. The mining industry started to decline in the early 1920s, and in 1922 the railroad discontinued service. The community is listed on the National Register of Historic Places as the St. Elmo Historic District. It is one of Colorado's best preserved ghost towns.

St. Elmo was originally named Forest City but was later changed because of the multitude of towns with the same name. The name St. Elmo was chosen by Griffith Evans, one of the founding fathers, who was reading a novel with the same title.