The XTERRA Trail Run World Series is a globally recognized trail running series that spans more than 30 events across over 20 countries, offering an inclusive platform for both elite and amateur runners. The series showcases the natural beauty of diverse terrains, ranging from mountains and forests to deserts and coastlines. Each race in the series typically includes a range of distances, from half-marathons (15-34 km) to full-marathons (35 km+), making the series accessible to runners of various skill levels.

Notable Events in the Series:

1. XTERRA Sugarloaf: Held at Sugarloaf Mountain, Maine, this event is a pinnacle series event. Runners compete in technical, challenging courses that showcase the rugged beauty of Maine's wilderness, including steep climbs and scenic descents through Sugarloaf’s trails.​
2. XTERRA McDowell Mountain Trail Run (Arizona): Taking place in February, this event challenges runners with a 43k marathon and a 24k half-marathon through Arizona's desert landscape, featuring cholla forests and cactus fields
3. XTERRA Oak Mountain Trail Run (Alabama): This race, part of the XTERRA Americas Trail Run Championship, is held in Oak Mountain State Park and offers distances up to a marathon. It draws runners from across the Americas and features a mix of flowing singletrack and technical terrain.
4. XTERRA Black Canyon Trail Run (Arizona): This event, known for its adventurous route, includes river crossings, sandy trails, and panoramic desert views. It offers marathon and half-marathon distances, and is part of the Arizona XTERRA Trail Run series.

The series emphasizes not only competition but also community, offering a space where trail running enthusiasts can connect and explore new environments while competing for points that contribute to the overall rankings. The top performers from each event are invited to compete in the exclusive XTERRA Trail Run World Championship.