Newcastle is a small town in County Down, Northern Ireland. The seaside resort lies on the Irish Sea coast at the base of Slieve Donard, one of the Mourne Mountains, and is known for its sandy beach and the Royal County Down Golf Club. The town lies within the Down District Council area. The town has all the usual seaside attractions - amusements, restaurants and takeaways, caravan parks, a boating lake, a bowling green and golf course, harbour, parkland and promenade. It also has many pubs. It is twinned with New Ross, County Wexford.