The Munising, Marquette and Southeastern Railway (MM&SE) was a short-line railroad that operated from 1911 until 1923 in the central Upper Peninsula of the US state of Michigan.
It was controlled by Cleveland-Cliffs, an iron ore and timber extraction conglomerate,[1] and its successor-in-interest is the Lake Superior and Ishpeming, a railroad that continues to operate as of 2024.
This Lawson–Big Bay line also served Marquette, the central Upper Peninsula's largest city.
[3] As timber dwindled and was replaced by less profitable pulpwood, Cleveland-Cliffs interests consolidated the MM&SE into another line they controlled, the Marquette-based Lake Superior and Ishpeming Railroad (LS&I); the 1923 merger ended the MM&SE's existence.
All but a short spur of the last segment, the former main line to Munising, ceased operations in 1979.