Hilgay is a civil parish in Norfolk, England, 4 miles (6.4 km) from Downham Market. It covers an area of 33.38 km2 (12.89 sq mi) and had a population of 1,341 at the 2011 Census. For local government purposes, it falls within the district of King's Lynn and West Norfolk.
Other places nearby are Fordham, Ryston, Southery and Denver.
Hilgay village sits on a raised isle, some 66 feet (20 m) above the surrounding fenland. Its elevation has become more pronounced as the draining of the fenland has caused the ground to shrink. It was notable in Saxon and early Norman times for the large numbers of fish and eels found there. Hilgay Old Bridge still crosses the river, but the newer A10 road bypass crosses just below it.
The scholar and poet Phineas Fletcher (1580 -1650) became chaplain to Sir Henry Willoughby, who presented him in 1621 to the rectory of Hilgay, Norfolk, where he married and spent the rest of his life.
George William Manby, who lived for much of his life in Hilgay, is buried in the churchyard, and his memorial celebrates his invention of a rocket to send a line to ships in distress. Prototypes were tested from the roof of the church tower, and he was awarded £2,000 by Parliament, as use of the device had saved 230 lives by 1823.
There was once a Hilgay railway station on the Fen Line.