The event began as the “Falls to Gasworks Relay” in 1983, beginning at Mt. Si High School near Snoqualmie Falls and ending at Gasworks Park in Seattle. In 1999, the event was moved to the Snoqualmie Valley and was renamed the Mt. Si. Relay & Ultra Run. In 1999 the solo run was 52.1 miles, and in 2000 it was changed to a 50.0 miles. In 2003, a 50K solo run was added and the name was changed to Mt. Si Relay & Ultra Runs.