Denver Marathon

Denver Marathon takes place on May 15, 2027, in Denver, Colorado, at the foot of the Rocky Mountains. The program runs from the 5K (3.1 mi) up to the full marathon (26.2 mi), by way of a 10K (6.2 mi) and a half marathon (13.1 mi), with a relay and a children's race alongside. Start times are not listed in our records.

Denver sits a mile above sea level, and no amount of fitness removes that from the equation: a runner arriving from the coast should expect to give up three to five percent of their usual marathon pace. Either race within twenty-four hours of landing, before the body registers the altitude, or arrive two weeks early — the window in between is where visitors feel worst.