Based in Boise, ID, this event series offers two separate challenges you can tackle individually or together: the Idaho Trail Ultra Series (ITUS) requires finishing 4 events of 50K or longer, while the Idaho Trail Series (ITS) asks you to complete 4 races between 10-30 miles. Completing either challenge earns you a custom award (a running jacket for ITUS or a hoodie for ITS), and both series use a points system to crown the top 6 male and female finishers with Dirty Dozen Awards. With 10 races spread across Idaho from various race directors, you'll experience some of the region's most stunning trail running courses.