- Malcolm Davis, Artist, Papers, 1970/201514
- Margaret Hoffman Collection, 1893-19699
- Marian McQuade Papers, 1853/19952
- Marshall W. Fishwick Collection, 1700/2007, bulk 1923/200712
- Martin Judy Family Papers, 1857/2012, bulk 1890/198610
- Martin Luther Brown, Warden, Moundsville Penitentiary Records, 1910/19202
- Mary McKendree Johnson, Collector, Papers, 1932/195811
- Matthew Mansfield Neely (1874-1958), Politician, Papers, 1900/195428
- Melvin C. Snyder, Congressman, Papers, 1946/19534
- Metropolitan Theatre, Morgantown, Records, 1910/2000207
- Mildred Hassler Layman, Family and Genealogy Papers, 1750/19521
- Monongalia County (W. Va.) Court Records and Miscellaneous Papers, 1774/1954918
- Monongalia County Historical Records, 1792/1982, bulk 1878/1976170
- Monroe County (W. Va.) Court Records and Miscellaneous Papers, 1751/1927217
- Morgan County Court Records, 1820/188059