Lower Nanamocomuck TrailNorth Conway, New Hampshire
Two hours north of Boston, and just outside the mountain playground of North Conway, the Lower Nanamocomuck Trail is a classic New England backcountry trail—beginning, appropriately, at a restored covered bridge. This 7.5-mile point-to-point trail starts as gravel road that eventually merges into a sublime (and sometimes quite muddy) singletrack that follows the Swift River. There's minimal elevation gain, with some rocky features, and a few narrow log bridges over creeks and marshy sections.
Poison Spider MesaMoab, Utah
The Utah desert outpost of Moab is known more as a mountain biking mecca, but the region's crackled Navajo Sandstone slickrock trails make it just as much a trail runner's paradise. Assuming you have a hydration pack to help you endure the often intense heat, you could pick just about any trail and not go wrong. Our choice is the 13-mile loop that encompasses Poison Spider Mesa west of town and has a variety of technical features, plus amazing vistas of jagged red rock topography in all directions, as well as the snowcapped La Sal mountains in the distance.
Palos/Sag Valley Trail SystemsPalos Park, Illinois
A hidden gem on the outskirts of Chicago, these adjacent forest preserve parks offer more than 30 miles of dirt trails through thick deciduous forests and deep ravines, past wetland lakes and marshes, and across wide-open meadows. Among the best routes are the hilly 12-mile Maple Lake loop and the nearby 6-mile Swallow Cliff Woods loop, which encircles a series of morainal hills created by retreating glaciers 12,000 years ago. The Chicago area is known for its network of flat, crushed gravel rail trails (including the 61-mile Illinois Prairie Path and 31-mile Des Plaines River Trail), but the rolling single-track trails in Palos are carved out of a secluded natural setting that belies the trails' close proximity to the bustling city and suburbs.
Double Oak TrailPelham, Alabama
This 17-mile rolling single-track loop in Alabama's largest state park winds around a large lake and through lush green hardwood valleys, with several punchy climbs that ascend to pine-studded ridges. Rocky terrain, large roots, and other technical features make for a tough but rewarding run.
Mesa TrailBoulder, Colorado
The running republic of Boulder is one of the country's top trail towns, serving up more than 200 miles of routes in close proximity to the city. Perhaps none is more universally appealing than the 7-mile Mesa Trail, a mildly technical singletrack route that connects a network of trails beneath and around the iconic Flatirons mountain facades, and which can lead to rugged runs to the top of 8,144-foot Green Mountain or 8,461-foot Bear Peak. World-class ultrarunners, marathoners, and triathletes use Mesa as a staple of training, but it's an equally invigorating route for anyone who enjoys an epic run.
Berryman TrailPotosi, Missouri
Situated in the heart of the Mark Twain National Forest, the Berryman trail is a rocky single-track that winds through the low shoulders of the Ozark Mountains. This 24-mile trail offers a rewarding roller coaster ride as it traverses classic lower Midwestern forests, alternating between shaded woodsy creek bottoms and ridgetops with cheek-chapping winds.
Maah Daah Hey TrailMedora, North Dakota
With its colorful rock formations, scenic big sky vistas, and seemingly endless grasslands (where wild horses still roam freely), the Maah Daah Hey is a geological timepiece in the rugged North Dakota Badlands. This former Native American trade route (the name is a Mandan Indian phrase that means "been around for a long time") connects the north and south units of the Theodore Roosevelt National Park and, at 96 miles, is one of the longest single-track trails in the U.S. One of the best running sections meanders from the south trailhead in Sully Creek State Park in Medora through the Petrified Forest inside the national park.