- O'Donnell & Naccarato Inc
- O'Donoghue & O'Donoghue LLP
- Office Support Employment Svc
- Official Court Reporters
- OLC
- Old City Arts Assn
- Old City Civic Assoc
- Old City Data Svc
- Old City Dental Office
- Old City Flowers
- Old City Food Market
- Old City Ironworks Inc
- Old City Music School
- Old City Nail Salon
- Old City Pizza & Restaurant
- Old City Special Svc Dist
- Old First Reformed United Chr