From A Wiki of Ice and Fire
Leafy Lake is a lake in the Reach. It lies within the lands of House Webber. The mouth of the Chequy Water flows into it.
Leafy Lake was once under the domain of House Osgrey. Since Lady Rohanne Webber married Ser Eustace Osgrey it may or may not now be back under the control of House Osgrey. There was once a cadet branch of the Osgreys, called House Osgrey of Leafy Lake. Ser Clifford Conklyn also had a claim on it.