- Jim Hart, Madison County Commissioner, MACo President (09/2018 – 09/2019)
- Shane Gorder, Richland County Commissioner, MACo 1st Vice President (09/2018 – 09/2019)
- Doug Martens, Rosebud County Commissioner, MACo 2nd Vice President (09/2018 – 09/2019)
- Bill Barron, Lake County Commissioner, MACo Immediate Past President (09/2018 – 09/2019)
- Mike McGinley, Beaverhead County Commissioner, MACo Fiscal Officer (09/2018 – 09/2019)
- Greg Chilcott, Ravalli County Commissioner, Appointed* (10/2018 – 09/2019)
- Eric Bryson, MACo Executive Director, Trust Secretary
*NOTE: The Current MACo Urban Counties Representative is not from a member county; therefore, the Trustees made an appointment on October 11, 2018.
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) and the MACo Executive Director.