Hike or ride smooth singletrack on this 7.2-mile lasso-loop, which climbs gently through rich scrubland and ponderosa forest to a killer mountainside overlook.

Cruise 5.2 miles along gentle foothills, Ireland-esque pastures, and past an old sawmill to a vista overlooking Boulder Canyon and the Front Range.

Downtown and need a post-meeting fix? This heart-pounding 4.3-mile scramble in Apex Park gives new meaning to that old runner's high.

Hike lonely trails filled with Yosemite-like granite formations in Lost Creek Wilderness on this 15.4-mile out-and-back up the Retirement Range's highest peak.

Bag two peaks on this 9-mile, fido-friendly loop around Boulder's signature Flatirons.

Ride some of western Colorado‰Ûªs finest singletrack with tight turns, long descents, and stunning red sandstone on this 7.4-mile heart-pounder.

Ascend North America's tallest dunes for a day surrounded by alpine peaks, a desert valley, and shifting mountains of sand on this 6.6-mile loop in America's newest national park.

Hike into the core of Indian Peaks Wilderness on this 13.6-mile overnight, which leads past waterfalls to a sunbleached valley and a sweet lakeside campsite.

Thanks to only a little elevation gain, this 7-mile loop offers flatlanders great rewards (big views, wildlife, solitude) without much suffering. Pack plenty of water and sunscreen.

Follow this 9.9-mile loop through vibrant wildflower displays and past snow-fed streams to a huge alpine lake with unbeatable campsite views of Mount Meeker.