On September 9 th and 10 th , Chattanooga will host the 2017 Ironman 70.3 World Championship. The organizers of the Ironman contests expected more than 185,000 athletes to race in over 100 Ironman 70.3 races around the world this year. From those races more than 4000 athletes will be coming to Chattanooga to compete in the 2017 Ironman 70.3 World Championship. From the City of Chattanooga's Web site: Public activities start at 6pm on Wednesday, September 6 with the “Made in Tennessee”