100mi January ultramarathons in United States (Southwest)

Flat, open route on the Northeast Texas Trail with gravel, dirt, pavement, and grass sections through small towns and rugged backcountry

Desert singletrack and foothill paths in Estrella Mountain Regional Park, with Sonoran scenery and 100K or 100-mile options.

Rugged Nevada desert ultra on a demanding 12.5-mile loop: 90%+ singletrack, technical terrain, steep climbs, fast descents, and Black Mountain.