City of Trees Marathon

The City of Trees Marathon takes place each October in Boise, Idaho, offering marathon, half marathon, 10K, 5K, and virtual race formats. The road course winds through tree-lined streets, parks, and along the Boise Greenbelt, typically under cool fall weather ranging from the low 40s to mid 60s Fahrenheit. Compared to large urban races, this event is smaller, with historical fields of approximately 150 marathon finishers and 400 half marathon finishers, contributing to a more local atmosphere. The course is largely an out-and-back on pavement, featuring a generally flat profile with some rolling sections. Participants will run alongside the Boise River, close enough to hear its flow, and catch glimpses of the foothills. The Greenbelt's open nature means the route can be less predictable than a closed downtown circuit, with potential for adjustments due to construction, flooding, sinkholes, or wildlife. Aid stations are positioned about every two miles, typically providing water, sports drink, fuel, and first aid. All finishers receive an award.