Barrios de Pennsylvania O
- Oak Lane-East Oak Lane (8)
- Oak Tree Hollow (2)
- Oakwood (1)
- Old City (78)
- Old Uptown Harrisburg (14)
- Olde Kensington (59)
- Olney (19)
- Orchard Park (8)
- Outer Kenhorst/Shillington (2)
- Outer Lancaster (49)
- Outer Wilkes-Barre (9)
- Outer York/Valley View/Grantley (7)
- Outlet Area (2)
- Outlying South Allegheny (14)
- Overbrook (2)
- Overbrook (53)
- Oxford Circle-Castor (24)