Marcellus A. McClain was born in Des Moines, Iowa on January 8, 1889. He spent his early childhood in Worcester, MA and lived there until 1903 when he and his brother, E. J. McClain joined their father ranching in the Bitterroot Valley of Montana. In 1906, M. A. McClain began to work for the Northern Pacific Railroad as a fireman-engineer. He continued at Northern Pacific until 1959. During that time he married Mary Agnes “Babe” Dore and had four children, Leo, Phyllis, Marjorie and Gene. M. A. McClain invested in the Missoula community. He served in the Montana House of Representatives as a Democrat from Missoula during the 26th Assembly, 1937-1939. M. A. McClain continued throughout his life to be active in Missoula community affairs assisting in the creation of the Orange Street Underpass access to the North Side and the Scott Street Overpass to the North Side. He also supported the continued operation of Missoula General Hospital on the North Side. M. A. McClain died on January 5, 1980 in Missoula, Montana and is buried in the St. Mary Cemetery.
From the guide to the M. A. McClain Papers, 1937-1954, (University of Montana--Missoula Maureen and Mike Mansfield Library Archives and Special Collections)