RMRR Fall Marathon Training Series 2026

The race.

Rocky Mountain Road Runners offers the Fall Marathon Training Series in Thornton, CO, featuring four distances: 10 miles, 20 miles, 20K, and 30K. Races begin at 7 a.m. at Riverdale Ballfields (9830 Riverdale Road). Three race dates are available: August 30 (10 miles and 20 miles), September 13 (20K and 30K), and September 27 (10 miles and 20 miles). All courses are marked with mile markers and aid stations, officially timed, with ribbons awarded to distance winners. RMRR members receive a 25% discount at checkout. Dogs and running strollers are not permitted on courses.