Looking for locations in Thornton? USLocalGyms helps you find all location in Thornton, CO. There are a total of 0 gyms in Thornton. On the map below you can see all the locations of gyms in the city. Going to the page of the gym from the list, you can see the opening hours, services, read reviews of those who have used the services. If you have visited in Thornton, please leave a review about your visit. The closest locations to you are: