The department serves unincorporated Williamson County, the Town of Nolensville, Thompsons Station, City of Spring Hill, City of Franklin, and City of Fairview. Within these jurisdictions, the department supports 5 law enforcement (Spring Hill Police, Franklin Police, Sheriff’s Office, Nolensville Police, and Fairview Police), 7 fire (Spring Hill Fire, Franklin Fire, Williamson Fire-Rescue, Williamson Rescue Squad, Nolensville Fire, Arrington Fire, and Fairview Fire), and 1 emergency medical department (Williamson Emergency Medical Services).