Sourdough Trail is an awesome singletrack trail that takes you along alpine trails and winds through high elevation forests. Every once in awhile the forests open up and you get to see the stunning views of the surrounding mountains and valleys!<br />
This is a multi-use trail so be sure to share the path.
From Boulder, head up to Nederland. Go right(north) on Highway 72 for aboug 7 miles. Turn left onto County Road 116 (there's a sign for the University of Colorado Mountain Research Station). go about .5 mile to the parking lot on the left, trail starts across the road, this is the south end of the trail.<br /><br /><br /><br /><br /><br /><br /><br /><br /><br /><br /><br /><br /><br /><br /><br /><br /><br /><br /><br /><br /><br /><br /><br /><br /><br /><br /><br /><br /><br /><br /><br />http://maps.google.com/maps?q=nederland,+co&hl=en&ll=40.027549,-105.524712&spn=0.036871,0.06669&hnear=Nederland,+Boulder,+Colorado&t=m&z=14<br /><br /><br /><br /><br /><br /><br /><br /><br /><br /><br /><br /><br /><br /><br /><br /><br /><br /><br /><br /><br /><br /><br /><br /><br /><br /><br /><br /><br /><br /><br /><br />There's another trailhead further north, from Ward, head up Brainard Lake Rd, there's a large nice new parking area on the right just before you get to the Toll gate. For this stretch of Sourdough, most of the climbing is done heading North from the South end, and mostly downhill going South.
http://www.tripleblaze.com/trail.php?c=3&i=115