Essex Constabulary was formed in 1840. In 1965, the force had an establishment of 1,862 officers.
Southend-on-Sea Borough Police was established by the county borough of Southend-on-Sea, England, in 1914. In 1969 Southend-on-Sea Borough Police amalgamated with Essex Constabulary to become the Essex and Southend-on-Sea Joint Constabulary. This merger was campaigned against by the council and the local MPs. Colchester also at one time had its own police force.
The title was shortened to Essex Police in 1974. In April 2000, it took over parts of the county in the south-west (Loughton, Waltham Abbey, Chigwell and Buckhurst Hill) formerly in the Metropolitan Police Area.