- Doug Martens, Rosebud County Commissioner, MACo President (09/2020 – 02/2021)
- Jason Strouf, Custer County Commissioner, MACo 1st Vice President (02/2020 – 02/2021)
- Roman Zylawy, Mineral County Commissioner, MACo 2nd Vice President (02/2020 – 02/2021)
- Shane Gorder, Richland County Commissioner, MACo Immediate Past President (02/2020 – 02/2021)
- Mike McGinley, Beaverhead County Commissioner, MACo Fiscal Officer (02/2020 – 02/2021)
- Denis Pitman, Yellowstone County Commissioner, Urban Counties Representative (02/2020 – 02/2021)
- Eric Bryson, MACo Executive Director, Trust Secretary (Non-Voting)
The Board of Trustees consists of the MACo Executive Committee (President, 1st Vice President, 2nd Vice President, Immediate Past President, Fiscal Officer, and Urban Counties Representative).