Predominantly in the Peel region, the Yalgorup is the largest national park on the Swan Coastal Plain extending just south of Mandurah to Myalup in the Harvey Region.

It includes ten magnificent lakes and the famous Lake Clifton Thrombolites (one of the first life forms known on earth. Lake Preston extends 20 kilometres south to Myalup.

The lakes that characterise the park lie in the depressions between a series of coastal dunes. Reflecting this underlying structure, the ten lakes of Yalgorup National Park form three distinct lines parallel to the coast.

Lake Preston near Myalup is extremely elongated and lies closest to the coast.