December ultramarathons in United States

Technical multi-lap course through Oak Mountain State Park, starting and finishing by Tranquility Lake

1.1-mile loop with 340 feet of climbing per lap, steep ascents, runnable sections, and a field descent on double track logging road

Steep 0.35-mile loop with 89 meters elevation gain per lap, repeated up to 100 times for Everest-equivalent climbing and cumulative elevation awards

Certified 2.022-mile soft chat loop at former golf course, multiple timed races, strict cutoff rules, fully stocked aid, RV camping and tent space

Flat, sea-level loops with minimal elevation gain and a lively event village atmosphere

Challenging 2.5-mile loop every 45 minutes, elimination format with no breaks, last runner standing wins, endurance-focused test

Scenic Lake Ray Roberts routes with well-groomed single-track and technical segments featuring roots, rocks, and varied North Texas terrain

Classic Northern California terrain: flowing singletrack, rolling dirt paths, stout climbs, heat, exposure, and wide-open vistas.

Technical 10.5-mile loop with rolling hills and diverse terrain through Caloosahatchee Regional Park’s scenic Green, Black, and Blue trails

Scenic desert landscapes, rolling singletrack, quick ascents and descents on a mix of classic and newer trails in McDowell Mountain Regional Park

Coastal trails through Point Mugu State Park, panoramic ocean views, rugged climbs, and rejuvenated landscapes with blooming flora

Alpine mountain loops on Dartmouth Skiway’s rugged slopes, steep climbs, and varied terrain with significant elevation changes in a wintry setting

100-mile course on a 7.2-mile loop amid long leaf pines and palmettos, gentle 225-foot elevation per loop, wildlife sightings, and illuminated night sections

Loop through rolling Spangler Hills desert terrain on jeep roads, singletrack and sandy washes, with expansive views of the Southern Sierra.

Flat rail trail with gentle inclines, sub-1500 feet elevation gain, downtown Farmville start, High Bridge crossings, generous 100k cutoff

Two-mile looped trail along the Chattahoochee River with self-serve aid stations and a community-focused, no-frills atmosphere

Rugged winter ultramarathon with 136 feet elevation gain per mile, persistent climbs and descents at Twin Valley's chilly, scenic terrain

Smooth, rolling singletrack on a no-repeat 50K with wooded loops, changing scenery, and around 1,600 feet of elevation gain.

Out-and-back loops on the Tower Trail in Sleeping Giant State Park, 600'+ elevation gain per loop, winding gravel paths, repetitive ascents and descents

Rugged technical trails with roots, rocks, steep elevation changes, and intermittent Boston skyline views in classic New England woodland