According to NSW Primary Industries, the basin extends through approximately of coastline from Newcastle in the north to Durras Lake (near Batemans Bay) in the south. From Durras Lake the western boundary continues in a line through Lithgow to around Ulan (near Mudgee). To the north the boundary extends along the Liverpool Range to a point north of Muswellbrook, and then runs back to the coast at Newcastle. To the east the basin continues to the edge of the continental shelf.