Dirty Bismark – Marshall Mesa

Route Description for Dirty Bismark – Marshall Mesa

Dirty Bismark is a 24.6 km loop that rides through the rolling foot hills in view of the iconic Boulder Flatirons. The ride varies from single track to maintained gravel trails and snakes around the treeless plains of the flatland. With only minimal technical sections, this is a good ride to get in some miles while not kicking your butt too badly. This trail also gives you the feeling of being in the middle of nowhere, even when there are major cities and highways never too far away.

The description is based on riding the loop clockwise. As you head out from the trailhead along Marshall Valley, the trail traverses a grassy hill towards the east. After passing through a couple of cattle gates and side roads, via Community Ditch, Cowdrey Draw and Mayhoffer Singletree Trail; the trail becomes a maintained, city gravel trail that is shared with hikers and dog walkers.

Continue along Meadowlark Trail to Coalton Park Trailhead. A turn towards the west puts you on a straight climb up an old dirt road, Coalton Trail, to the top of Davidson Mesa. From this vantage point, you will be able to see far back into the mountains and see the snow-capped Indian Peaks and Longs Peak (4,346 m).

Eventually you will return to single track via High Plains and Greenbelt Plateau Trail. As you make your way back to the Marshall Mesa Trailhead, the riding gets a little more exciting, with the final section of trail being the most technical.

Insider Hints for Dirty Bismark – Marshall Mesa

• Pay to Park at the trailhead unless your vehicle is registered in Boulder or there is free parking just across the street in a large gravel parking lot.
• Check Boulder Trail Conditions here.