Scarning Fen is a 4-hectare (9.9-acre) nature reserve west in Dereham in Norfolk.

[1] It is a Nature Conservation Review site, Grade I,[2] and is part of Potter and Scarning Fens Site of Special Scientific Interest[3] and Norfolk Valley Fens Special Area of Conservation.

[4] This small reserve has chalky valley mire, carr and grassland.

Twenty-nine nationally scarce invertebrates have been recorded, and it is the only site in the county for the small red damselfly.

There are a number of rare plants, including liverworts and mosses.