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> Boulder, CO: Sourdough Trail
A Colorado altitude thrill ride, this 11.5-mile out-and-back snakes through tight conifer tunnels, navigating rock gardens, log piles, and balance-testing switchbacks.
The USGS topographic map below is custom-centered on Boulder, CO: Sourdough Trail. Customize a map online, and we'll print and ship you a
large-format waterproof map. Custom prints start at only $9.95 for an 18" x 24" field map, but you can build huge 5' x 8' wall posters too!