# List of places in Pennsylvania: O

This list of cities, towns, unincorporated communities, counties, and other recognized places in the U.S. state of Pennsylvania also includes information on the number and names of counties in which the place lies, and its lower and upper zip code bounds, if applicable.
| Name of place | Number of counties | Principal county | Lower zip code | Upper zip code |
| Oak Forest | 1 | Greene County | 15370 | |
| Oak Grove | 1 | Adams County | | |
| Oak Grove | 1 | Clearfield County | 16858 | |
| Oak Grove | 1 | Monroe County | | |
| Oak Grove | 1 | Montour County | | |
| Oak Grove | 1 | Schuylkill County | 17963 | |
| Oak Grove | 1 | Washington County | | |
| Oak Grove | 1 | Westmoreland County | 15658 | |
| Oak Hall | 1 | Centre County | 16827 | |
| Oak Hill | 1 | Allegheny County | 15137 | 15145 |
| Oak Hill | 1 | Clearfield County | 16845 | |
| Oak Hill | 1 | Lackawanna County | 18507 | |
| Oak Hill | 1 | Lancaster County | | |
| Oak Hill | 1 | Venango County | | |
| Oak Hills | 1 | Butler County | | |
| Oak Lane | 1 | Montgomery County | 19012 | |
| Oak Lane | 1 | Philadelphia County | 19126 | |
| Oak Park | 1 | Montgomery County | 19446 | |
| Oak Park | 1 | Northumberland County | 17857 | |
| Oak Ridge | 2 | Armstrong County | 16245 | |
| Oak Ridge | 1 | Clearfield County | | |
| Oak Shade | 1 | Lancaster County | 17566 | |
| Oak Tree | 1 | Indiana County | | |
| Oakbottom | 1 | Lancaster County | 17566 | |
| Oakbourne | 1 | Chester County | | |
| Oakbrook | 1 | Berks County | | |
| Oakdale | 1 | Allegheny County | 15071 | |
| Oakdale | 1 | Luzerne County | 18224 | |
| Oakford | 1 | Bucks County | 19053 | |
| Oakhurst | 1 | Cambria County | | |
| Oakland | 1 | Allegheny County | 15213 | |
| Oakland | 1 | Armstrong County | | |
| Oakland | 1 | Cambria County | | |
| Oakland | 1 | Lawrence County | 16101 | |
| Oakland | 1 | Mercer County | | |
| Oakland | 1 | Susquehanna County | 18847 | |
| Oakland Beach | 1 | Crawford County | 16316 | |
| Oakland Mills | 1 | Juniata County | 17076 | |
| Oakland Township | 1 | Butler County | | |
| Oakland Township | 1 | Susquehanna County | | |
| Oakland Township | 1 | Venango County | | |
| Oaklane Manor | 1 | Montgomery County | 19012 | |
| Oakleigh | 1 | Dauphin County | 17111 | |
| Oakley | 1 | Susquehanna County | | |
| Oaklyn | 1 | Northumberland County | 17801 | |
| Oakmont | 1 | Allegheny County | 15139 | |
| Oakmont | 1 | Cambria County | 15904 | |
| Oakmont | 1 | Delaware County | 15139 | |
| Oakryn | 1 | Lancaster County | 17563 | |
| Oaks | 1 | Montgomery County | 19456 | |
| Oaktree Hollow | 1 | Bucks County | | |
| Oakvale Boulevard | 1 | Butler County | 16002 | |
| Oakville | 1 | Cumberland County | 17257 | |
| Oakville | 1 | Westmoreland County | 15650 | |
| Oakwood | 1 | Lawrence County | | |
| Obelisk | 1 | Montgomery County | 19492 | |
| Oberlin | 1 | Dauphin County | 17113 | |
| Oberlin Gardens | 1 | Dauphin County | 17113 | |
| Obold | 1 | Berks County | | |
| Ochre Mill | 1 | Luzerne County | | |
| Odell | 1 | Washington County | | |
| Odenthal | 1 | Cambria County | 15946 | |
| Odenwelder | 1 | Northampton County | 18042 | |
| Odin | 1 | Potter County | 16915 | |
| O'Donnell | 1 | Jefferson County | | |
| Ogden | 1 | Delaware County | 19061 | |
| Ogden Park | 1 | Delaware County | 19062 | |
| Ogdensburg | 1 | Tioga County | 17765 | |
| Ogdonia | 1 | Sullivan County | | |
| Ogle | 1 | Butler County | 16046 | |
| Ogle Township | 1 | Somerset County | | |
| Ogletown | 1 | Somerset County | 15963 | |
| Ogontz | 1 | Montgomery County | 19117 | |
| O'Hara Township | 1 | Allegheny County | | |
| Ohio Township | 1 | Allegheny County | | |
| Ohio Township | 1 | Beaver County | | |
| Ohiopyle | 1 | Fayette County | 15470 | |
| Ohioview | 1 | Beaver County | 15052 | |
| Ohioville | 1 | Beaver County | 15059 | |
| Ohl | 1 | Jefferson County | 15864 | |
| Oil City | 1 | Cambria County | 15925 | |
| Oil City | 1 | Venango County | 16301 | |
| Oil Creek | 1 | Venango County | 16301 | |
| Oil Creek Township | 1 | Crawford County | | |
| Oilcreek Township | 1 | Venango County | | |
| Oklahoma | 1 | Clearfield County | 15801 | |
| Oklahoma | 1 | Westmoreland County | 15613 | |
| Okome | 1 | Lycoming County | 17739 | |
| Olanta | 1 | Clearfield County | 16863 | |
| Old Boston | 1 | Luzerne County | 18641 | |
| Old Clarendon | 1 | Warren County | 16313 | |
| Old Concord | 1 | Washington County | 15329 | |
| Old Crabtree | 1 | Westmoreland County | 15650 | |
| Old Cranberry | 1 | Luzerne County | | |
| Old Enon | 1 | Lawrence County | 16120 | |
| Old Forge | 1 | Delaware County | 19060 | |
| Old Forge | 1 | Franklin County | | |
| Old Forge | 1 | Lackawanna County | 18518 | |
| Old Fort | 1 | Centre County | | |
| Old Frame | 1 | Fayette County | 15478 | |
| Old Furnace | 1 | Beaver County | | |
| Old Junction | 1 | Somerset County | 15501 | |
| Old Line | 1 | Lancaster County | 17545 | |
| Old Lycoming Township | 1 | Lycoming County | | |
| Old Meadow | 1 | Westmoreland County | 15683 | |
| Old Mountain House | 1 | Fulton County | | |
| Old Orchard | 1 | Northampton County | 18042 | |
| Old Port | 1 | Juniata County | 17082 | |
| Old Shade Furnace | 1 | Somerset County | | |
| Old Side | 1 | Centre County | | |
| Old Stanton | 1 | Westmoreland County | 15672 | |
| Old Zionsville | 1 | Lehigh County | 18068 | |
| Old Zollarsville | 1 | Washington County | | |
| Oleona | 1 | Potter County | | |
| Oleopolis | 1 | Venango County | 16301 | |
| Oley | 1 | Berks County | 19547 | |
| Oley Furnace | 1 | Berks County | 19522 | 19547 |
| Oley Line | 1 | Berks County | 19547 | |
| Oley Township | 1 | Berks County | | |
| Oliphant Furnace | 1 | Fayette County | 15401 | |
| Oliveburg | 1 | Jefferson County | 15764 | |
| Oliver | 1 | Fayette County | 15472 | |
| Oliver Mills | 1 | Luzerne County | | |
| Oliver Township | 1 | Jefferson County | | |
| Oliver Township | 1 | Mifflin County | | |
| Oliver Township | 1 | Perry County | | |
| Olivers Mills | 1 | Luzerne County | 18702 | |
| Olivet | 1 | Armstrong County | 15618 | |
| Olmsted | 1 | Potter County | | |
| Olmsville | 1 | Tioga County | | |
| Olney | 1 | Philadelphia County | 19120 | |
| Olyphant | 1 | Lackawanna County | 18447 | |
| Onberg | 1 | Indiana County | 15701 | |
| Oneida | 1 | Butler County | 16001 | |
| Oneida | 1 | Schuylkill County | 18242 | |
| Oneida Junction | 1 | Luzerne County | 18201 | |
| Oneida Township | 1 | Huntingdon County | | |
| Oniontown | 1 | Mercer County | | |
| Onnalinda | 1 | Cambria County | 15921 | |
| Ono | 1 | Lebanon County | 17077 | |
| Onspaugh Corners | 1 | Crawford County | | |
| Ontario | 1 | Washington County | 15324 | |
| Ontelaunee | 1 | Berks County | 19605 | |
| Ontelaunee Township | 1 | Berks County | | |
| Opp | 1 | Lycoming County | 17756 | |
| Oppenheimer | 1 | Bedford County | | |
| Oppermans Corner | 1 | Chester County | 19425 | |
| Option | 1 | Allegheny County | 15236 | |
| Orange | 1 | Luzerne County | 18612 | |
| Orange Township | 1 | Columbia County | | |
| Orangeville | 1 | Columbia County | 17859 | |
| Orbisonia | 1 | Huntingdon County | 17243 | |
| Orchard Beach | 1 | Erie County | 16428 | |
| Orchard Crest | 1 | Cumberland County | | |
| Orchard Crossing | 1 | Blair County | 16686 | |
| Orchard Hill | 1 | Westmoreland County | 15666 | |
| Orchard Hills | 1 | Armstrong County | 15613 | |
| Orchard Hills | 1 | Delaware County | 19063 | |
| Orchard Park | 1 | Lancaster County | 17601 | |
| Ore Hill | 1 | Blair County | 16673 | |
| Ore Valley | 1 | York County | 17403 | |
| Orefield | 1 | Lehigh County | 18069 | |
| Oregon | 1 | Lancaster County | 17540 | |
| Oregon Hill | 1 | Lycoming County | 16938 | |
| Oregon Township | 1 | Wayne County | | |
| Oreland | 1 | Montgomery County | 19075 | |
| Oreminea | 1 | Blair County | 16693 | |
| Oreville | 1 | Berks County | 19539 | |
| Orient | 1 | Fayette County | 15420 | |
| Oriental | 1 | Juniata County | 17045 | |
| Oriole | 1 | Lycoming County | 17740 | |
| Ormrod | 1 | Lehigh County | 18037 | |
| Ormsby | 1 | McKean County | 16726 | |
| Orners Corner | 1 | Blair County | 16601 | |
| Orrstown | 1 | Franklin County | 17244 | |
| Orrtanna | 1 | Adams County | 17353 | |
| Orrton | 1 | Berks County | | |
| Orrville | 1 | Allegheny County | 15144 | |
| Orson | 1 | Wayne County | 18449 | |
| Orvilla | 1 | Montgomery County | 19440 | |
| Orville | 1 | Allegheny County | 15144 | |
| Orviston | 1 | Centre County | 16864 | |
| Orwell | 1 | Bradford County | 18837 | |
| Orwell Township | 1 | Bradford County | | |
| Orwig | 1 | York County | | |
| Orwigsburg | 1 | Schuylkill County | 17961 | |
| Orwin | 1 | Schuylkill County | 17980 | |
| Osborn | 1 | Mercer County | | |
| Osborne | 1 | Allegheny County | 15143 | |
| Oscar | 1 | Armstrong County | | |
| Osceola | 1 | Clearfield County | | |
| Osceola | 1 | Tioga County | 16942 | |
| Osceola Mills | 1 | Clearfield County | 16666 | |
| Osceola Township | 1 | Tioga County | | |
| Osgood | 1 | Mercer County | 16125 | |
| Oshanter | 1 | Clearfield County | 16830 | |
| Ostend | 1 | Clearfield County | 15757 | |
| Osterburg | 1 | Bedford County | 16667 | |
| Osterhout | 1 | Wyoming County | 18657 | |
| Oswayo | 1 | Potter County | 16915 | |
| Oswayo Township | 1 | Potter County | | |
| Ott Town | 1 | Bedford County | 15537 | |
| Ottawa | 1 | Montour County | 17821 | |
| Otter Creek Township | 1 | Mercer County | | |
| Otterbein | 1 | Franklin County | | |
| Otto | 1 | Northumberland County | | |
| Otto Township | 1 | McKean County | | |
| Ottown | 1 | Bedford County | 15537 | |
| Ottsville | 1 | Bucks County | 18942 | |
| Outcrop | 1 | Fayette County | 15478 | |
| Outlet | 1 | Luzerne County | 18612 | |
| Outwood | 1 | Schuylkill County | 17963 | |
| Oval | 1 | Lycoming County | 17759 | |
| Overbrook | 1 | Allegheny County | | |
| Overbrook | 1 | Philadelphia County | 19151 | |
| Overbrook Hills | 1 | Montgomery County | 19151 | |
| Overfield Township | 1 | Wyoming County | | |
| Overholt Acres | 1 | Westmoreland County | 15642 | |
| Overleigh | 1 | Montgomery County | 19004 | |
| Overlook | 1 | Lancaster County | 17601 | |
| Overlook | 1 | Northumberland County | | |
| Overlook Heights | 1 | Centre County | | |
| Overlook Springs | 1 | Lehigh County | | |
| Overshot | 1 | Bradford County | | |
| Overton | 1 | Bradford County | 18833 | |
| Overton Township | 1 | Bradford County | | |
| Overview | 1 | Cumberland County | 17053 | |
| Owassee | 1 | Tioga County | | |
| Owens Corners | 1 | Erie County | | |
| Owensdale | 1 | Fayette County | 15425 | |
| Owl Hollow | 1 | Bradford County | | |
| Owls Nest | 1 | Elk County | | |
| Owltown | 1 | Venango County | | |
| Oxford | 1 | Chester County | 19363 | |
| Oxford Township | 1 | Adams County | | |
| Oxford Valley | 1 | Bucks County | | |
| Oyster Point | 1 | Lancaster County | 17601 | |