Hainault Forest Country Park is one of the remaining sections of the former Forest of Essex in England. Epping Forest and Hatfield Forest are other examples. It is located in Hainault in the London Borough of Redbridge and its area is 136 hectares (336 acres)..
The forest, said to bear its name in deference to Philippa of Hainault, queen of Edward III, belonged to the abbey of Barking until the dissolution of the monasteries; it extended northwards to Theydon Bois (bois, "woodland"), east to Havering-atte-Bower, on the south to Aldborough Hatch, and westwards to Leytonstone. In a survey made for Henry VIII in 1544 its extent was some 3000 acres.
The forest land was condemned as waste by an Act of Parliament, 1851, disafforested, the deer removed, the old growth forest cut down, and the land divided for building lots, for a growing London.
After public pressure to retain some remnant headed by Edward North Buxton, a total of 804 acres (3.3 km2) of land, which included 253 acres (1.0 km²) of woodland and rough pasture) was bought for public use on 21 July 1906. It includes the Hainault Forest Golf Club and a large lake, as well as a farm, partly for rare breeds of animal.
The park is administered by the London Borough of Redbridge.