Colorado 13er (Half Marathon/10K/5K)

Colorado 13er is held on June 6, 2027, in Louisville, Colorado. The half marathon (13.1 mi) starts at 6:30 a.m., and the 10K (6.2 mi) and 5K (3.1 mi) at 6:40 a.m. No elevation gain is listed.

Louisville sits above 5,300 feet, which is enough to cost a sea-level runner a minute or more over a half marathon however fit they are: arrive the day before or two weeks before, but not three days before. The early start is deliberate in a Front Range June — by nine in the morning the sun is already doing real work, and the races are designed to be finished by then.