The name Lough key, derives from ce', the druid of nuadha of the silver arm, king of the tuatha de danann who, according to legend, was drowned when the waters of the lake burst forth from the earth.
The area around Lough Key and the nearby town of Boyle, in County Roscommon, have been inhabited for thousands of years.
In the 800-acre park, which surrounds Lough key, ring forts, are perhaps the oldest evidence of habitation. Five ring forts are contained within the park itself and many more can be seen in adjacent fields and woods.