Colfax Marathon The 9th Annual Colfax Marathon is Sunday, May 18. The 26.2 mile Denver course starts and finishes at City Park. To avoid street closures, check the route which takes takes runners west to Lakewood passing through many neighborhoods and part of the downtown business district. General Traffic: The marathon will have full and partial closures of westbound and eastbound Colfax from Aurora to Lakewood starting as early as 3 a.m. … Continue reading →