Barrios de Pennsylvania O
- Oak Lane-East Oak Lane (11)
- Oak Tree Hollow (2)
- Oakwood (2)
- Old City (69)
- Old Uptown Harrisburg (9)
- Olde Kensington (34)
- Olney (18)
- Orchard Park (5)
- Outer Kenhorst/Shillington (2)
- Outer Lancaster (48)
- Outer Wilkes-Barre (8)
- Outer York/Valley View/Grantley (3)
- Outlet Area (2)
- Outlying South Allegheny (18)
- Overbrook (4)
- Overbrook (51)
- Oxford Circle-Castor (16)