- Macy's1
- Mail and Express1
- Maine Democrat1
- Maine Manufacturing Company1
- Malloy Hat Co.2
- Manchester Beef Co.1
- Manewal-Lange Biscuit Co.1
- Mangelsdorf Bros. Co.1
- Mangelsdorf Seed Company1
- Manhanset House1
- Manhattan Oil Company1
- Manhattan Refrigerating Co.2
- Manhattan Storage and Warehouse Co.3
- Mannheimer Bros.1
- Manning, Bowman & Co.1
- Manning, Glover & Co.1
- Mansion1
- Manville Covering Co.1
- Marietta Paint & Color Co.1
- Marine Trust Company1
- Marinette Iron Works Co.1
- Marquette Hotel1
- Marshall, Kennedys & Co.1
- Marshall-Wells Company1
- Marshall-Wells Hardware Company1
- Martin Dawson, Manufacturing1
- Martin, Perrin & Co.2
- Martin, Spencer & Co.1
- Marvin Bakery, U. S. B. Co.1
- Marvin's Safe Co.1
- Marxsen and Witte1
- Maryland Casualty Company1
- Mast, Buford & Burwell Co.1
- Masury, Young & Co.2
- Mattewan Company1
- Mauser Manufacturing Co.1
- Maybrook Co-operative Stores1
- Mayer & Loewenstein2
- Mayo-Knapp Abstract Co.1
- Mayor, Lane & Co.2
- McCall Company1
- McCray Refrigerator Co.2
- McDonald Bro's Co.2
- McFarland & Jenks1
- McIntosh & Co.2
- McIntosh Huntington Co.1
- McShane Bell Foundry1
- Mead, Mason & Co.1
- Mellin's Food for Infants and Invalids1
- Merchant & Co.1
- Merchant's Savings Loan & Trust Company1
- Merchants Hotel1
- Merchants National Bank1
- Merchants and Manufacturers Exchange of New York1
- Meriden Britannia Company1
- Merkle-Wiley Broom Co.2
- Merle & Heaney Manufacturing Co.1
- Merrell & Co.1
- Mersereau Mfg. Co.1
- Metropolitan Furniture House1