Study any Boulder trail map and it's easy to see why this city is a mecca for dirt junkies. Prime running trails wind across the vast open space and mountain parks system that encircles the city, offering everything from wide-open fire roads to rocky, technical ascents. Whether you like to charge hard through the hills or prefer to trot along at a relaxed pace, or hit the trail for an hour or a day, Boulder has the perfect trail for you.
So pick a starting point and lace up your shoes. Some days you might set out with a plan; others, you might prefer to explore. You could run on Boulder’s vast network of trails for weeks and hardly ever hit the same route. Follow your foot’s fancy and remember to look up often enough to take in the views. Here, a quick and dirty guide to the best trail running in Boulder.
The Mesa Trail is a classic Boulder trail run, stretching more than seven miles along the foothills from Chautauqua Park to the South Mesa Trailhead near Eldorado Springs. Running the full length is like taking a tour of Boulder’s mountain parks, with scenic vistas of the dramatic Flatirons, ponderosa pine forests, colorful wildflower meadows, and the rolling plains to the east.
The trail meanders up and down through the trees and is mostly shaded, although the southern end is fairly exposed. Be prepared for some rocky sections and steps with railroad ties.
It’s a burly 13.4 miles and 3,250 feet of elevation gain if you go all the way out and back. Alternatively, shuttle a car or arrange for a pickup and run it one way. Running north to south is slightly more downhill and gives you the option of soaking your tired feet in South Boulder Creek at the end.
Flatirons Vista Loop
Flatirons Vista is an ideal starting point for trail runs of almost any length. Two loops are readily accessible from the trailhead—Prairie Vista is 1.9 miles, and the Flatirons Vista Loop is 3.3 miles. Pick your length or string both together. The terrain is fairly gentle, with some slight hills. As you wind through a patchwork of forest and prairie, take in the sweeping views of Shadow Canyon, the foothills, and the Flatirons to the north.
If you want to tack on some more mileage, drop down to the Doudy Draw trail network, which branches off the Flatirons Vista Trail. If you’re up for doing a giant loop, continue from there through the new underpass on 93 to Marshall Mesa. Return on the east side of 93 via the Greenbelt Plateau Trail, which will lead you back to the Flatirons Vista Trailhead.
Wonderland Lake Park is a tranquil, lovely park in North Boulder, just three miles from downtown but a world away from its hustle and bustle. Take a lap or two around the lake, or use the park as a launching point for trails father afield. The Foothills Trail heads north out of the park and leads along the edge of the foothills—hence the name.
Several trails branch off the Foothills Trail and head up into the hills. These trails see less traffic than some of their cousins farther south, so they’re suitable if you’re seeking a bit of solitude. Old Kiln and Wonderland Hill seem to be almost secretive (although they are well marked). Keep going north on the Foothills Trail past Lee Hill Drive and you’ll eventually hit the Hogback Ridge Loop, a lovely trail that is never crowded, even on summer weekends.
Mount Sanitas has a lot of options for a relatively small mountain. For trail runners, it’s the perfect playground to develop strength and endurance. While the trails aren’t long, they make up for it with gritty elevation gain.
A favorite is to run up the 1-mile Dakota Ridge Trail and return via the 1.3-mile Valley Trail, a quick loop with 600 feet of elevation gain that you can make longer if you run it from town.
If you’re up for a bigger burn, run the full loop to the top of Mount Sanitas. It can be done in either direction, but the classic route is to ascend the Mount Sanitas Trail—which starts out brutally steep and then levels off intermittently, providing good interval training. From the summit, descend the East Ridge Trail, then use the Valley Trail as a cool-down. The full loop is just 3.1 miles but taxes the lungs with 1,343 feet of elevation gain.
Mount Sanitas is a prime test piece for trail runners. Many runners work their way up to a full jog of the summit trails by “hiking the steps and running the flats,” a proven strategy for reaching the top in record time (or at least personal record time).
At the base of the iconic Flatirons, Chautauqua Park is the starting point for many trails that traverse the foothills west of Boulder. Runners will love Enchanted Mesa, which starts just behind Chautauqua Dining Hall and climbs up into the hills. Return via the Mesa Trail to make it a loop. If that’s not quite long enough, tack on the Bluebell-Baird Trail and circumnavigate Chautauqua Meadow.
If you’re up for a longer jaunt, take your pick of dozens of options. The Mesa Trail heads south for miles, the First and Second Flatiron Trail snakes up between two giant rock slabs, and Royal Arch is a steep burn. Or embark on an exploration mission with no set plan.
The Sage Trail is one of the city’s most beautiful, secluded, and peaceful escapes, nestled in a small valley below a mesa just north of Boulder near Boulder Reservoir. The trail running options are plentiful and offer a nice contrast to the rocky (and often crowded) mountain trails.
Just under 3 miles, the Sage Trail is a well-maintained loop that starts out following a farmer’s irrigation ditch and circles a working farm where cattle and horses graze. Two laps on the Sage Trail make an ideal 10K training circuit. For added mileage, tack on the Eagle Trail to the east (which connects to the Boulder Reservoir), the Eagle Connector Trail to the south (which connects into the North Boulder / Boulder Valley Ranch network), the Left Hand Trail to the north (which links to farther out dirt roads suitable for running), and the Foothills Trailhead to the west (which connects to the Wonderland Lake trail network). You can create your own run of nearly any distance by combining this incredible trail system.
The trail can get a little hot in the summer due to the lack of shade, but this quickly becomes a bonus in the autumn and winter. Snow melts quickly, so this is a good choice when mountain trails are covered in ice.
Races: Boulder Rez Half Marathon (permit pending), Boulder Rez Marathon (permit pending), Boulder Sunrise 5K , Boulder Sunset 5K
Organizations: Boulder Trail Runners , Revolution Running
Retailers: Boulder Running Company , Fleet Feet , Newton Running Lab