- Ontonagon Country, Inc1
- Ontonagon Herald Company1
- Osborn, Chase S. (Chase Salmon), 1860-19491
- Osceola County Road Commission1
- Otsego County Chamber of Commerce1
- Otsego County Road Commission1
- Otsego Land Use Planning Committee1
- Ott, R.1
- Ottawa County (Mich.)1
- P.S. Duval & Co.1
- Pettibone, Darwin A., 1827-18941
- Phelps, Humphrey,active 19th century,publisher.1
- Phelps, Lee R.1
- Public Roads Administration1
- Public Service Commission1
- R. Burger & Company.1
- Rand McNally and Company, engravers.1
- Raynolds, W. F. (William Franklin), 1820-18941
- Raynolds, W. F. (William Franklin), 1820-1894, surveyor1
- Risdon, Orange1