• Jefferson County Open Space has a great variety of trails, and is where I do almost all of my riding!. This excellent page has maps and trail descriptions.
• Boulder Mountain Bike Alliance
• Apex Park, Golden
• Sections of the Colorado Trail near Denver
• The Devil's Thumb Park Loop (west of Denver)
• The Jackson Creek Loop (Douglas County, southwest of Sedalia)
• The Jefferson Creek and Red Cone Trails (Park County)
• The Red Mesa Loop and Strawberry Jack Trail (Jefferson County)

Sourdough Trail near Boulder

Sourdough Trail near Boulder and a few miles from Nederland, offers 12.3 miles of rocky singletrack and considered moderate-difficult. Don’t be fooled by the whitebread-sounding name. It’s definitely multi-grain.

Hall Ranch near Boulder

Also near Boulder, you’ll find Hall Ranch, a 9.3-mile loop or hard-packed singletrack with very technical sections and extreme difficulty. Keep your eyes peeled for deer, rabbits, ground hogs and squirrels, and be prepared for mountain lion sightings along the trail. Do your homework to avoiding run-ins with these beautiful, but potentially dangerous, beasts and you’ll be fine (hint: don’t run).