- Martinsburg Chamber of Commerce (Martinsburg, W. Va.)4
- Martinsburg Chamber of Commerce (Martinsburg, W. Va.). Industrial Committee.1
- Martinsburg Fire Company (Martinsburg, W. Va.)1
- Martinsburg High School (Martinsburg, W. Va.)2
- Martinsburg Public Library (Martinsburg, W. Va.)1
- Martinsburg-Berkeley County Chamber of Commerce (W. Va.)2
- Martinsburg-Berkeley County Convention and Visitors Bureau (Martinsburg, W. Va.)3
- Marvel, Mason Edwin, 1921-1
- Mary Ingles Trail Associates (Winfield, W. Va.)1
- Maryland Artificial Breeding Cooperative.1
- Maryland Genealogical Society.1
- Maryland. Comptroller's Office.1
- Maryland. Hall of Records Commission.3
- Maryland. Publicity Commission.1
- Mason, George, 1725-1792.1
- Mason, J. A.1
- Mason, J. M. 1
- Mason, J. W. (John W.), 1842-1917.1
- Mason, James Murray, b. 1838.5
- Mason, John L.2
