Park Gate Down is located at (Ordnance Survey reference ) and covers seven hectares on the eastern slopes of a dry valley on the dip slope of the North Downs. The reserve is predominantly chalk grassland although the eastern fringes consist of a mixture of woodland and scrub which is partially situated on a layer of clay with flints that caps the chalk. In the south eastern corner of the reserve is a disused chalk pit and the western and northern area of the reserve borders on Elham Park Wood. To the south of the reserve is an area of land managed under the Countryside Stewardship Scheme which is being reverted from arable land to chalk downland.