100mi October ultramarathons in United States

Mountain ultramarathon along the Wasatch Front with 20,869 feet of vertical gain, rugged singletrack, exposed ridges, and scenic canyon trails

Rugged 100-mile route through the San Gabriel Mountains' primitive wilderness, featuring rough terrain and scenic, largely untouched backcountry

Flat, fast point-to-point course along the scenic Hennepin Canal from Sterling to Colona, featuring historic locks, lift bridges, and autumn farmland views

10-mile loop on Blue Wing, Koasati, and Whoa Mule trails with flat, muddy paths, tree roots, and views of Lake Bistineau and cypress forests

Double out-and-back route on asphalt, gravel, and dirt trails with over 10,000 feet of elevation gain through Stub Stewart State Park and Vernonia Lake

50- or 100-mile clockwise loop around Prescott, linking standout singletrack and backcountry trails across rugged central Arizona terrain

104-mile out-and-back on Westmoreland Heritage and West Penn Trails, 7,392 feet of elevation gain, Morosini Reserve and parks in peak autumn colors

Scenic Ouachita Mountains route featuring forest roads, rugged jeep trails, and 12,000 feet of elevation across runnable, deceptively tough hills

Remote gravel roads through Flint Hills prairie, open rangeland, rolling hills, 6,000 feet of climbing, scenic out-and-back and loop sections near Eureka and T.

Scenic rails-to-trails course along the New River with vibrant fall foliage, historic train trestles, gentle dirt and crushed gravel path, and minimal elevation

Rugged singletrack and rolling terrain on looping courses through hardwood forests and around kettle lakes at Chain O’Lakes State Park

Mountain routes near Los Angeles featuring Big Bear Lake views, Sugarloaf Mountain ascents, and descents into Siberia Canyon

10.48-mile pine barrens trail loop in Rocky Point, with ultramarathon distances from 50K to 150 miles and flexible start times

Paved, illuminated 2-mile loop with minimal elevation at Sparks Marina, featuring lakeside scenery, sandy beaches, and flexible distance or timed challenges

Rolling hills and national scenic beauty on the Virginia Creeper Trail with easy crew and spectator access

Historic Midstate Trail routes through mountains, fields, and river crossings, with border crossings and New England autumn scenery

Rugged single-track ultramarathons on the Gerard Hiking Trail, with over 17,000 feet of elevation gain through Oil Creek State Park's scenic, demanding terrain

Fast, flat course on the picturesque Towpath Trail through Northeast Ohio scenery

Counter-clockwise loop course with centralized aid station, personal pit areas near start, heated restrooms, and chip-timed lap tracking

Winding single-track trails, rolling service roads, and open prairie across 800 scenic acres at Farmdale Reservoir in central Illinois