The Local Government Act 1919, part 29, enabled the governor to proclaim "county councils", which are groupings of local government areas (at the time, municipalities and shires) who wished to cooperate in the provision of services.
While like other county councils in New South Wales, it was established by proclamation of the Governor, the Local Government (Town and Country Planning) Amendment Act 1945 inserted a new part 12A in the Local Government Act 1919, containing special legislative provisions to apply to Cumberland County Council.
[2] In 1948 the Council published the County of Cumberland planning scheme, a framework for accommodating expected postwar growth in the Sydney Basin.
The objectives of the County Council were often in conflict with the aims of many State Government departments.
For instance, the County Council's plans called for a green belt to encircle metropolitan Sydney, while the NSW Housing Commission wished to use much of this land to build new low-density public housing estates in areas such as Blacktown and Liverpool.