Ashton-Tetonia Trail - If you're hoping to"heel" the winter blues, then follow the mushers over to Ashton, Idaho, this February 16,17, and 18 for the annual American Dog Derby. Since 1917, dogsled enthusiasts have converged on Ashton to participate in the longest-running dogsled race in the lower 48 states. The main course runs from Ashton to Cascade Corner of Yellowstone National Park, but the derby offers a host of other competitions, including a mutt run, weight pull, snow sculpture contest and much more.