Castlewellan is a town in County Down, Northern Ireland. It is alongside Castlewellan Lake and Slievenaslat mountain, 11 miles (18 km) southwest of Downpatrick. It lies between the Mourne Mountains And Slieve Croob. It had a populace of 2,392 individuals in the 2001 Census.
Castlewellan has a wide fundamental road which goes through two primary squares lined with chestnut trees. The town was planned by a French engineer for the Annesley Family. The Annesley family did not generally own the area as they purchased it off The Maginess Family.