The City of Trees Marathon in Boise utilizes the Boise Greenbelt system. The river can be unpredictable, and systems and entities that govern the local Greenbelt are constantly dealing with challenges. Typical issues are created due to sidewalk construction, sinkholes, flooding, etc. During the run, you may encounter wildlife that may cause a delay in your progress and/or a change in your planned route. Or you may cause your own delay to stop and listen to the amazing sounds this course creates.