Knee Hill forms the boundary between the modern boroughs of Bexley and Greenwich and the ancient parishes of Plumstead and Erith. After 1889, it also formed the boundary between the counties of Kent and London.

The ancient woodland on either side of the road was purchased in two parcels, one in 1877 and the other in 1894, by the Metropolitan Board of Works and its successor, the London County Council, to safeguard it from development.