Thorne Moors National Nature Reserve is an area of almost 73ha (180 acres) owned and managed by the Nature Conservancy Council. It contains the best surviving example of a cut-over raised mire within the Thorne, Goole and Crowle Moors, which were once part of a huge wetland site of bog, fen and marsh known as the Humberhead Levels, situated around the head of the Humber.