Like much of the neighbouring area, Lambourne was thickly wooded in the Middle Ages with forest gradually being cleared for agriculture. A few remnants of the historic Hainault Forest are found in the southern fringe of the parish, and now form part of a country park.
Its population was 505 in 1801 rising to 904 by 1841, remaining at about that level for the next century.
Historically Lambourne was included in the hundred of Ongar. It formed part of the Ongar Rural District from 1894 to 1955, and then Epping and Ongar Rural District until it became part of Epping Forest District in 1974.