The original Knockreer House, built for the Earl of Kenmare in the 1870s, burned down in 1913; the present house was built on the same site in 1958 and is now home to a national-park education centre. It isn't open to the public, but its terraced gardens have magnificent views across the lakes to the mountains.
From the park entrance opposite St Mary's Cathedral, follow the path forking right, past the cute thatched cottage of Deenagh Lodge, built in 1834.