Hilgay Heronry is a 1.8-hectare (4.4-acre) biological Site of Special Scientific Interest south of Downham Market in Norfolk, England.

[1][2] This small wood has a nationally important breeding colony of grey herons, with around forty nests each year in larch and ash trees.

Nearby drainage dykes on The Fens provide feeding grounds.

[3] The site is private land with no public access.