Hartslock Nature Reserve is located on the north side of the Thames between Whitchurch and Goring-on-Thames, Oxfordshire. The site is owned by The Wildlife Trust for Berks, Bucks & Oxon (BBOWT) and managed by its staff and volunteers.

The reserve is a beautiful south facing, unimproved chalk downland hill with stunning views over the Thames and Goring Gap region. The grassland is surrounded by ancient hedges and mixed Yew woodland and, although it is only small (11-acres or 4.4 hectares), it is home to a very wide variety of plants and animals, some of which are extremely rare. For this reason the government has designated it and the surrounding area a 'Site of Special Scientific Interest' (SSSI) and the whole Goring Gap region is an 'Area of Outstanding Natural Beauty' (AONB).

The wildlife on Hartslock is typical of unimproved chalk downland but unfortunately, due to modern farming methods and the increasing pressures on land in the south of England, this kind of habitat is becoming increasingly rare.