City of Trees Marathon

The City of Trees Marathon is a race series held in Boise each October. Participants can choose from marathon, half marathon, 10k, 5k, or virtual race formats. The in-person courses utilize the Boise Greenbelt, making it a road-and-path event that follows the Boise River, distinct from a closed downtown circuit. The course traces the river corridor as water from the Sawtooth and Boise mountains transitions from rocky canyons into the city. Runners will often hear the river, but the Greenbelt's condition can necessitate adjustments due to construction, sinkholes, flooding, or wildlife. All City of Trees participants receive a finisher award. Long-sleeve shirts, sponsor items, and post-race refreshments are provided when available.