Highway patrol and state police officers are often referred to as "State Trooper". Historically, a troop was a small cavalry unit. Many state police forces originated as mounted paramilitary forces who were stationed in barracks like soldiers, hence the term "trooper." A state trooper goes by the title "trooper", as in "Trooper John Smith". Some agencies, particularly on the east coast, refer to their state police offices as "barracks," although troopers generally do not reside there. Other state police forces, particularly highway patrols as in California, have always modeled themselves after police officers who simply commute to work like ordinary civilians. Like police officers, they use the title "officer." Other states use the term "Patrolmen" in reference to members of the State Police or Highway Patrol.