Castle Hayne is a census-designated place (CDP) in New Hanover County, North Carolina, United States.

The forest provided the region's major industries through the 18th and most of the 19th century: naval stores and lumber fueled the economy both before and after the American Revolution.

After suffering crippling losses at Guilford Court House, the British withdrew all forces back to Fort Johnson and abandoned plans to occupy North Carolina.

This prompted the British to attack Yorktown, Virginia instead, which brought an end to the war.

As of the 2020 United States census, there were 1,243 people, 559 households, and 267 families residing in the CDP.

17.4% were of Irish, 14.8% English, 7.3 United States or American, 5.7% Scots-Irish, 5.6% Subsaharan African, 5.1% German and 5.0% French ancestry according to Census 2000.