Mud Lake is a Boulder County Open Space park located off of the Peak to Peak Highway near Nederland. The trails are wide and easy, perfect for some MTB hot laps at altitude in the summer or cross-country skiing in the winter. Trails connect to Hurricane Hill to the east and Caribou Ranch to the northwest (but at this time there is no MTB at Cairbou Ranch).
Although the trails themselves can be a little ho-hum, BMA gave this area a coolness factor of 4 because of the beautiful lake and picnic area - bring the kids out for some riding in the woods, then relax with a picnic by the lake, how can it get any better? Mud Lake is at an elevation of approximately 9000', thus the aerobic factor of 5.
As with all County parks, the trails are open sunrise to sunset (no night riding).