Westmoreland County was one of the original Nineteen Counties in New South Wales and is now one of the 141 Cadastral divisions of New South Wales. It is to the west of Sydney in the Blue Mountains. Coxs River is the border to the north, and the Wollondilly River to the east. Campbells River is the border in the north-east, where the county extends to near Bathurst, with the Fish River part of the border.