The River Room is the fine-dining restaurant at Galgorm Resort, set in the manor house with views over the River Maine and the resort's wooded grounds. The cooking is contemporary Irish, working with local and seasonal produce — Antrim beef, seafood from the north coast, vegetables from small producers around the region. The menu changes to reflect what's available, and the kitchen has a solid reputation for technique without being showy about it.
Booking is essential, particularly at weekends, and the prices are at the upper end of what you'd expect in Northern Ireland. It's a special-occasion restaurant rather than somewhere for a casual dinner. Non-residents can book without staying at the hotel, and doing so is probably the most straightforward way to eat well in the Ballymena area.
The resort also runs a more casual bar and grill option in the same complex, which covers the same ground at lower prices and without the need to book as far ahead.