The northern boundary is contiguous with the Midwest southern boundary and runs from Green Head on the coast eastward to Karoun Hill Nature Reserve.
In the north-east the boundary follows the State Barrier Fence (limit of agriculture).
The eastern boundary is south from Koolyanobbing to Frank Hann National Park.
The southern boundary extends from Frank Hann National Park west to near Moodiarrup.
The western boundary is north through Williams to Toodyay and it then extends westward to the coast at Wilbinga.
