Institution
- Lincoln High School Preservation Alumni Association, Incorporated104
- Lutheran Theological Southern Seminary135
- Lysol1
- Maine Development Commission1
- Mapleine1
- Margaretta Childs Archives at Historic Charleston Foundation4
- Marion Harris Neil1
- Marlboro County Public Library System20
- Marlborough County Historical Museum, Bennettsville1
- Marlborough County History Museum, Bennettsville1
- Maxwell House, Brooklyn, New York1
- Maytag1
- McConnon & Co.1
- Mepkin Abbey4
- Merrell-Soul Co.1
- Metropolitan Life Insurance Company1
- Metropolitan Life Insurance Company Press1
- Metropolitan Life Insurance Company, New York1
- Middleton Place Foundation1,643
- Miller & Hart1