Hornchurch Cutting is an 0.8-hectare geological Site of Special Scientific Interest in Hornchurch in the London Borough of Havering. It is at the southern edge of the Anglian ice sheet 450,000 years ago, the most extreme ice age during the Pleistocence ice ages of the last 2.58 million years. (Technically, the most southerly point reached by an ice sheet during the Quaternary was The Dell, a few metres south of St Andrew's Church.) 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 construction of the Romford to Upminster railway line in 1892. He found a five-metre thickness of boulder clay overlaid by sand and gravel. An excavation in 1983 revealed extensive Jurassic fossils and rocks that had been carried from the Midlands by the ice sheet.
It is 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.
- "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.