Moor Mill Quarry, West is a 0.16-hectare (0.40-acre) geological Site of Special Scientific Interest in How Wood in Hertfordshire. The local planning authority is St Albans City and District Council. It was notified in 1992 as representing the former Moor Mill Quarry SSSI, which was lost to landfill operations. It is listed by the Geological Conservation Review. There is no access to the deep quarry, which is partly filled with water, but it can be viewed by crossing the railway line at How Wood station and turning south to follow the east side of the Abbey Line.