Imogene Pass Run
Sandwiched between Ouray and Telluride, this 17.1-mile race peaks at the 13,114-foot Imogene Pass. Its founder, Rick Trujillo, first ran the pass solo in 1974; since then, the event has exploded in popularity. More than 1,500 people registered to run in 2013. "I'm just astounded at what this event has turned into," Trujillo says. "I've done many races in Europe, but I don't know if any of them could be more spectacular than Imogene Pass on a beautiful day."
Quivering Quads Half Marathon
As the name implies, Quivering Quads is a tough one, but the atmosphere is relaxed. "QQ brings the we're-all-in-this-together vibe of an ultramarathon to the popular 13.1-mile distance," says race director David Spetnagel. "Racers support each other as they run challenging singletrack, and then celebrate as a group at the finish." Looping through Cuivre River State Park, the course includes plenty of hills—and they'll likely be muddy due to spring showers, so wear your knobbiest shoes.
The North Face Endurance Challenge—New York
Bear Mountain State Park, New York
This beginner-friendly ultramarathon and 10K is held 40 miles north of Manhattan in Bear Mountain State Park. The race begins on the shores of the Hudson River, runs through the foothills of the Catskill Mountains, and concludes with live music at the finish line. "It's an incredibly rugged and rocky course," says Jordan McDougal, who won the 50-mile event in 2013. "But the scenery makes it all worthwhile; it's the only race I come back to every year."
Pengelly Double Dip
Named after Missoula mountaineer David Pengelly and two nearby ice-cream-cone-shaped peaks, the Pengelly Double Dip runs 13 miles through the Sapphire Mountains and includes 2,700 feet of climbing. "For the past three years," says race director Kevin Twidwell, "finishers have been awarded a beer growler—and our post-run party is sponsored by Draught Works, a local brewery." Because it travels through national forest land, this event is limited to 200 participants, so sign up right away when registration opens in April.
Great Adirondack Trail Run
Keene Valley, New York
This wild, 11.5-mile trail run up the back side of Hopkins Mountain, then down to Keene Valley, is an Adirondacks favorite—and that's how locals want to keep it. "If Outside includes us in a roundup, I worry we'll get completely swamped with applicants, and that's not what we want," explains Vinny McClelland, who organizes the event. "Even without that level of exposure, our race fills up in the first 15 minutes every year, exactly because of its one-of-a-kind course."
La Luz Trail Run
Albuquerque, New Mexico
If you've ever wanted to race nine miles up a mountain, here's your chance. Runners start in the Sandia foothills, ascending 1.8 miles on a paved road before hitting the dirt singletrack that winds up another 7.2 miles to the top of 10,678-foot Sandia Crest. The trail, which amounts to more than 4,000 feet of climbing on a 12 percent grade, has been dubbed the Rockslide at its upper part because of an abundance of big, sharp boulders (and there's no medical aid on the course in case of a fall). Because La Luz is held in a wilderness area of the Sandia Mountains, the U.S. Forest Service caps the number of runners at 400. To make sure you don't get left behind, enter the lottery at UltraSignup.com during the first week of May.