Hornchurch Cutting is an 0.8-hectare geological Site of Special Scientific Interest in Hornchurch in the London Borough of Havering. It marks the southern extremity of the Anglian ice sheet 450,000 years ago, and is the most southerly point reached by any ice sheet in Britain during the Pleistocence ice ages of the last 2.58 million years. It is the type site for Hornchurch Till, boulder clay laid down by the ice sheet in the Ingrebourne Valley.
The site was discovered by geologist T. V. Holmes during the construction of the Romford to Upminster Railway Line in 1892. He discovered an 5 metre thickness of boulder clay overlain by sand and gravel. A further excavation in 1983 revealed extensive Jurassic fossils and rocks which had been carried from the Midlands by the ice sheet. The site is very important for establishing the glacial stratigraphy of southern Britain.
The site is located between Woodhall Crescent to the north and St Andrews Park and Maywin Drive to the south.
- "Geology Site Account, The Dell". The Essex Field Club. Retrieved 2012-06-03. Strictly, the furthest point south was The Dell, a few metres south of St Andrew's Church.
- "Geology Site Account, Hornchurch Railway Cutting". The Essex Field Club. Retrieved 2012-06-03.
- Natural England, Hornchurch Cutting citation
- Network Rail team help uncover ‘Birth of Britain’, 2011
- Channel 4, Birth of Britain, Episode 2, Ice, 2011
- "Map of Hornchurch Cutting SSSI". Natural England.