Cr Cornwell McKean was elected last month to replace Cr Matt Hannan in the role.
The internal councillor election also saw Carly Marriott elected as her Deputy Mayor.
Normally elected for two years, the terms had been reduced due to delays in holding councillor elections during COVID-19.
Cr Cornwell McKean and Cr Marriott will hold their positions up until the next councillor elections, in September next year.
Cr Cornwell McKean said she was honored to be Berrigan Shire’s first indigenous mayor.
“Thank you to my fellow councillors for their continued support,” she said.
“I look forward to serving Berrigan Shire for the remainder of my term.”
Cr Cornwell McKean also expressed “profound appreciation and thanks” to Cr Hannan for his seven years of service as mayor.
“Cr Hannan has been at the helm, tackling the challenging years we’ve had with floods, COVID-19 and their flow on effects,” she said.