These plains are a region of prime agricultural land bounded to the east by the Great Dividing Range, to the south by the Liverpool Range and on the west by the Warrumbungle Range. The area is drained by the Namoi River and its tributaries, the Mooki River and the Peel River. There are many depressions, across the plains, which remain as lakes for long periods after heavy rain. These plains are unusual in that many steep hills arise suddenly from the plains.