From the Wikipedia page , which includes a list of parishes.
Epping and Ongar Rural District was a rural district in the county of Essex, England. It was created in 1955 by the merger of the disbanded Ongar Rural District and most of the disbanded Epping Rural District, except the civil parishes of Great Parndon, Harlow, Latton, Little Parndon and Netteswell, which were largely transferred to the newly created Harlow Urban District at the same time. It was administered from Epping.
Since April 1, 1974 it has formed part of the District of Epping Forest, except for the civil parishes of Blackmore, Doddinghurst, Kelvedon Hatch, Navestock and Stondon Massey, which became part of the Borough of Brentwood (Wikipedia page ).