West Mercia Police (/ˈmɜːrsiə/), formerly the West Mercia Constabulary, is the territorial police force responsible for policing the counties of Herefordshire, Shropshire (including Telford and Wrekin) and Worcestershire in England. The force area covers 2,868 square miles (7,430 km2) making it the fourth largest police area in England and Wales. The resident population of the area is 1.19 million Its name comes from the ancient kingdom of Mercia.