Holme Fen is a National Nature Reserve in Cambridgeshire, covering 2.7 km². It is one of ten National Nature Reserves in the county. None of the National Nature Reserves in the county is larger.
The nearest railway station is Peterborough, about 8.7 km to the north. Woodwalton Fen and Upwood Meadows are among the National Nature Reserves within 7.6 km.