Since 1750, Glenarm has been the family seat of the McDonnell family, earls of Antrim; it's currently the home of Lord and Lady Dunluce. The castle itself is closed to the public – except during the Tulip Festival on the May bank-holiday weekend, and during the Dalriada Festival in July – but you can visit the lovely walled garden and take a walk around the estate along the castle trail. Admission is free for children under 12.
The estate's organic farm is renowned for its Glenarm shorthorn beef; the smokehouse produces organic smoked salmon. Both are sold at the Glenarm Castle Tea Room & Shop.