Boulder is a trail runner's dream. The network of trails in town make it possible to take a casual jog on the eastern mesas or hammer up to the summit of 8,000’ peaks. The Bolder Boulder 10k race is one of America’s classic running events and is the foremost of Boulder’s many organized races. For recreational running, the addition of the Highway 93 Underpass in south Boulder connects two major trail systems -- Marshall Mesa and Doudy Draw -- creating lots of options and loops from 30 minute runs to your own personal marathon. Running Mount Sanitas and Green Mountain are classic tests of vertical endurance -- there are plenty of great runs that gain over 2,000 vertical feet in about 3 miles. And just above town are Walker Ranch, Betasso Preserve, and Heil Ranch. Whatever your trail running preference, Boulder's got options galore and a running-friendly vibe.