The Castlereagh Macquarie County Council (CMCC) is a local government authority for noxious weed control in the Walgett, Coonamble, Warren, Gilgandra and Warrumbungle Shire Council areas. The CMCC is empowered to implement and enforce the Noxious Weeds Act 1993 on behalf of the constituent councils and the New South Wales State Government.

Under the Noxious Weed Act 1993 the CMCC is responsible for the control of noxious weeds by owner/occupiers of private land as well as roadsides and crown land. Councillors and weeds officers representing each council continue to develop, implement, co-ordinate and review noxious weed control policies and programs in the area using an integrated weed management approach.

The county council is empowered to implement and enforce the Noxious Weeds Act 1993 on behalf of the Walgett, Warren, Coonamble, Gilgandra and Warrumbungle Shire Councils in the area covered by these councils. The county council is responsible for the control and eradication of such weeds both in rural and urban areas.

The county council is also responsible for controlling noxious weeds on land under its jurisdiction , on roadsides and vacant Crown Land through special grants. It is also responsible for ensuring that all owner/occupiers of private land fulfill their obligations under the Noxious Weeds Act. This responsibility entails property inspections, the giving of advice and directions and the implementation of legal action if required.

The county council is funded by contributions from the constituent Shire Councils. In addition the county council receives money from the NSW government in the form of Noxious Weed Grants to assist it in undertaking its various functions with regard to noxious weed control. From time to time the county council also successfully obtains funding from natural resource organisations to undertake specific weed control projects.