Upper Big Bluestern Trail

Embark on the Bear Peak & South Boulder Summit loop, a difficult jogging route that challenges you with a significant elevation gain of 3028 feet (923 metres) over 9.0 miles (14.4 km). This demanding loop takes you up two of Boulder's highest peaks, offering sweeping 360-degree views of the Colorado Front Range, the city of Boulder, and the iconic Flatirons from viewpoints like the Fern Canyon Trail ridgeline. You will traverse diverse terrain, from broad dirt paths to rocky sections with steep steps and jumbled boulders, passing through lush forests and burn zones, all achievable in about 2 hours and 43 minutes.

Planning your visit requires preparation for a strenuous workout. The route includes sections that involve scrambling over exposed ridges and very steep rock steps, particularly on the Fern Canyon Trail. While generally accessible, be ready for highly technical terrain that demands good fitness and experience. Parking is typically available at trailheads that access this popular route, but it's always wise to arrive early, especially on weekends, to secure a spot.

This loop is renowned for its dual summit experience, allowing you to conquer two prominent peaks in one outing. The varied landscape, from dense forest to open, rocky ridges, showcases the unique ecology of the Boulder Open Space and Mountain Parks. It is a favorite among local joggers seeking a rigorous challenge and unparalleled vistas, making it a standout option for those who appreciate a truly rewarding high-altitude effort.