Deputy Premier John Barilaro announced the 'champion of Western NSW' would be honoured with a State Funeral in Cobar on Friday, February 19.

"Lilliane Brady OAM was the longest serving female mayor in NSW and will be formally acknowledged by the NSW Government for her decades-long commitment to regional NSW by way of a State Funeral," Mr Barilaro said.

"For 40 years Lilliane was a vocal advocate for her community and the broader western NSW region and fiercely fought for what she believed in.

"While small in stature, Lilliane was a giant of local government for the last four decades and her unrivalled passion for the people of Cobar was critical in seeing the advancement of the community through local projects and funding."

Cobar Shire Council announced on Sunday morning that Lilliane had died peacefully overnight.

"It is with great sadness and respect that we inform you on behalf of Cobar Shire Council that the Mayor, Lilliane Brady OAM, has passed away peacefully in Cobar overnight," the council said.

"Our thoughts and prayers are with her family and loved ones."

Cr Brady, who held the position of mayor at the time of her death, was 90-years-old.

She served as mayor in the town for more than 20 years in total, and sat on the local council for 40 years.

She had planned to retire this coming September.

Deputy Cobar Mayor Peter Abbott said Cobar had lost "its Capital C" with her death.

"Yes it is very hard, this news," Councillor Abbott said. "She was an absolute icon in this neck of the woods. I don't think I could do her justice by mustering enough words about her.

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