By Anderson-Ivor - Own work, CC BY-SA 4.0, 

It lies by the Irish Sea at the foot of Slieve Donard, the highest of the Mourne Mountains. Newcastle is known for its sandy beach, forests (Donard Forest and Tollymore Forest Park), mountains, and the Royal County Down Golf Club. The town lies within the Newry, Mourne and Down District.

The town aims to promote itself as the "activity resort" for Northern Ireland and its most special attribute is its location. The town has benefited from a multi-million upgrade which makes it a high quality seaside attraction. The town is twinned with New Ross, County Wexford, in the Republic of Ireland.