The Ashton to Tetonia Trail is a rail-trail conversion built on the former Teton Valley Branch of the Union Pacific Railroad from Ashton to Tetonia, Idaho. The trail is used for hiking, biking, horseback riding, cross-country skiing, snowshoeing, and snowmobiling. Access points are found at Ashton, Marysville, Bitch Creek, Felt, and Tetonia. It is managed through Harriman State Park under administration by the Idaho Department of Parks and Recreation.
The trail crosses Conant Creek at the Conant Creek Pegram Truss Railroad Bridge, a former railroad bridge built in 1911, which is listed on the National Register of Historic Places.
The trail occupies a portion of the former Teton Valley Branch of the Union Pacific Railroad. The original line was constructed from 1910, beginning in Ashton, to 1912, when it was finished in Victor. The Ashton-Tetonia Trail opened to public in 2010 and spans about two-thirds of the length of the original line.