- Lang, John C.1
- Langellier, A. L.1
- Lewis, I. T. (John Theophilus)1
- Lloyd, James T.1
- Longyear, John Munro, 1850-1922, compiler1
- Lyman, Benjamin Smith, 1835-19201
- Mangum, A. W.1
- Martin, Luther R..1
- Matthews-Northrup Company1
- Maull Co.1
- Mayo, Geo. U. (George U.)1
- McClelland, D.1
- Meisel, A. (Augustus)1
- Mendel, Edward, 1827-18841
- Merrell, H. B. (Harvey B.), publisher1
- Michigan Central Railroad Company1
- Michigan Mutual Life Insurance Company.1
- Michigan Syndicate1
- Michigan. Department of Commissioner of Railroads1
- Milwaukee Lith. & Engr. Co.1