Castle Espie is a wetland reserve managed by the Wildfowl and Wetlands Trust (WWT) on the banks of Strangford Lough, three miles south of Comber, County Down, Northern Ireland. It is part of the Strangford Lough Ramsar Site. It provides an early wintering site for almost the entire Nearctic population of Pale-bellied Brent Geese. The Castle which gave the reserve its name no longer exists. Castle Espie was officially opened as a Wildfowl and Wetlands Trust centre by Lady Scott on 4 May 1990. The site had previously been a limestone quarry, and also had a brickworks, pottery and lime kilns for producing lime from limestone, as well as part of a farm.