Vail is a census-designated place in Pima County, Arizona, United States. It is twenty-four miles southeast of Tucson. The population was 10,208 at the 2010 census. The area is known for the nearby Colossal Cave, a large cave system, and the Rincon Mountains District of Saguaro National Park, a top tourism spot within Arizona.Vail was originally a siding and water stop on the Southern Pacific Railroad. It was located on the last section of flat land before the train tracks followed the old wagon road into the Cienega Creek bed. Vail was named after pioneer ranchers Edward and Walter Vail, who established ranches in the area in the late 19th century. Vail deeded a right of way across his ranch to the railroad. Vail owned the Vail Ranch, his brother Walter Vail owned the nearby Empire Ranch, now part of the Las Cienegas National Conservation Area. In 2011 the residents of Vail began the process of incorporation to become a town.