Castlereagh is a community in the Canadian province of Nova Scotia, located in Colchester County. It was either named after Castlereagh in Northern Ireland or Robert Stewart, Viscount Castlereagh.
Once a bustling village, only a few houses remain in Castlereagh - the only people found there now tend to be those occupying seasonal camps, typically for hunting or logging.
Coordinates: 45°31′0.09″N 63°44′55.88″W / 45.5166917°N 63.7488556°W