100K road ultramarathons in North America

9-mile road loop from Kalama Valley Park, gentle elevation, Heartbreak Hill descent, support stations every 2.5 miles, cupless, sustainability focus

Flat, fast course on the NETT Trail with asphalt, gravel, soft ground, scenic bridge crossings, and starts and finishes at Paris, Texas' Eiffel Tower

Scenic routes across diverse terrain with 50K, 50 mile, and 100K options highlighting local landscapes

Technical singletrack and rugged trails through Jackson-Washington State Forest, with scenic southern Indiana views and a community hub at Pyoca Camp

Multi-distance road ultramarathon on a 3.34-mile loop through Hawaii Kai, featuring out-and-back segments and hydration stations at Kalama Valley Park

Scenic route along Pistol Creek in East Tennessee, with a lit course and a friendly, community-driven atmosphere

Point-to-point 100-mile and 100K road ultra along the Outer Banks: flat, exposed coastal roads, ocean views, strong winds, and notable bridges.

Certified loop course with officially measured 50K and 100K routes, built for fast benchmark performances and a competitive race-day atmosphere.

Fast, flat, USATF-certified downtown loop with 12- and 24-hour options, festive atmosphere, food trucks, music, and special buckle for 100 miles

Distance options including 50 miles, 100k, and 100 miles in Northern Colorado, with team and solo entries, camping, and community atmosphere

Scenic two-mile dirt loop on a 120-acre nature reserve with rolling hills, wildlife, shrinking time cutoffs, cup-less support, and space for personal tents.

Flat out-and-back route on asphalt and dirt paths, shared with cyclists and equestrians, featuring changing weather and a lively race atmosphere

Team relay from Frenchman’s Bar Regional Park to Vancouver Waterfront, looping through Clark County via city parks, sidewalks, bike lanes, and road shoulders