Boulder opens new North Sky Trail, a rare addition to the city’s cycling network a decade in the making

The City of Boulder has opened the North Sky Trail, a new 3.5-mile multi-use trail connecting the Foothills North Trail in North Boulder to Joder Ranch. The $1 million project, nearly a decade in the making, expands the city’s trail network for cyclists. 

The new singletrack meanders through grasslands on the west side of U.S. 36. Designed with cyclists in mind, it provides a link to trail networks in Left Hand Canyon, such as Heil Valley Ranch. The trail is accessible to less experienced riders, as it does not feature drops, jumps or berms.

The new trail is also open to people on foot or horseback. Dogs must be on a leash and are prohibited from May 1 to July 31 to protect bird nesting habitat, according to the city. E-bikes are prohibited.

The trail runs through a habitat conservation area, a designation used by the city to protect rare plants and animals. The area includes the Bell’s twinpod, a rare yellow-flowered perennial mustard plant found only on the Front Range, as well as rattlesnakes and horned lizards, according to the city.

In light of the area’s ecological significance, early proposals to build the trail sparked controversy. Some residents called for an alternative route on the east side of U.S. 36. In 2016, however, the Boulder City Council approved a plan to build the trail in its current location. 

“We feel like we’ve really hit that balance between visitor experience and protecting the natural resources,” Dan Burke, director of Open Space and Mountain Parks, said during a trail opening ceremony on Monday, July 22. 

To minimize ecological impacts, Burke said the city negotiated easements with private property owners to avoid ecologically sensitive areas, installed two bridges to keep people out of drainages where birds nest, and relocated certain plants. The trail also incorporates grade reversals, or brief dips in the trail, to help shed water and prevent muddiness.

Cyclists and volunteers were particularly involved in the construction of the trail. Over the past year, more than 800 volunteers contributed about 4,500 hours in labor, according to a city official. The Boulder Mountainbike Alliance, a cycling advocacy organization, even paid to rent an excavator to help with construction, according to Wendy Sweet, executive director of the Boulder Mountainbike Alliance.

“It was built with bikes in mind,” Sweet told Boulder Reporting Lab. “Nine years ago, when we advocated for the trail, we said we would show up and help build it.”

The North Sky Trail is likely a precursor to more trails in the area. The North Trail Study Area Plan, a long-range management plan for city open space, calls for the creation of the Mahogany Loop near Joder Ranch. The plan also suggests rerouting trails in the Boulder Valley Ranch and opening them to cyclists. This includes the Cobalt Trail, Hidden Valley Trail and the Degge Trail, where cyclists are currently prohibited.

The last time the city built a new trail open for cyclists was in 2015, with the construction of the Joder Ranch Trail, according to a city official. Prior to that was the Spring Brook Loop near Eldorado Canyon, which was completed in 2008.

“Building a new trail in Boulder is really exciting,” Sweet said. “It does not happen very often.”