Ashford Castle in County Mayo is among Ireland's most famous — not to mention most luxe — castle hotels. Prepare to be dazzled by the 800-year-old estate from the moment you enter through the magnificent stone gates. Each of the 83 rooms and suites is distinctively designed and done up in various bold hues like reds, yellows, and greens. The 350-acre property also boasts landscaped gardens, a tranquil spa, three bars, and six restaurants.