| Name | What | Region | Country | Lat | Long | Elev ft. | Pop est |
|---|---|---|---|---|---|---|---|
| Olanta | city | Pennsylvania | United States | 40.92 | -78.51 | 1669 | |
| Old Boston | city | Pennsylvania | United States | 41.29 | -75.77 | 1040 | |
| Old City | city | Pennsylvania | United States | 39.95 | -75.15 | 9 | |
| Old Clarendon | city | Pennsylvania | United States | 41.77 | -79.10 | 1669 | |
| Old Colonial Village | city | Pennsylvania | United States | 40.32 | -76.83 | 830 | |
| Old Concord | city | Pennsylvania | United States | 40.01 | -80.34 | 1669 | |
| Old Covered Bridge Estates | city | Pennsylvania | United States | 39.99 | -75.45 | 351 | |
| Old Crabtree | city | Pennsylvania | United States | 40.35 | -79.44 | 1158 | |
| Old Ferry | city | Pennsylvania | United States | 40.53 | -77.14 | 830 | |
| Old Forge | city | Pennsylvania | United States | 39.79 | -77.48 | 1128 | |
| Old Forge | city | Pennsylvania | United States | 41.37 | -75.73 | 830 | |
| Old Fort | city | Pennsylvania | United States | 40.84 | -77.67 | 1200 | |
| Old Frame | city | Pennsylvania | United States | 39.81 | -79.86 | 1102 | |
| Old Furnace | city | Pennsylvania | United States | 41.07 | -76.93 | 830 | |
| Old Furnace | city | Pennsylvania | United States | 40.80 | -80.17 | 1197 | |
| Old Gum Tree | city | Pennsylvania | United States | 40.67 | -79.52 | 1128 | |
| Old Mill Pointe | city | Pennsylvania | United States | 39.88 | -75.42 | 98 | |
| Old Mountain House | city | Pennsylvania | United States | 40.02 | -78.19 | 1669 | |
| Old Orchard | city | Pennsylvania | United States | 40.66 | -75.26 | 200 | |
| Old Port | city | Pennsylvania | United States | 40.53 | -77.39 | 830 | |
| Old Shade Furnace | city | Pennsylvania | United States | 40.15 | -78.83 | 2509 | |
| Old Sheffield | city | Pennsylvania | United States | 41.67 | -79.02 | 1669 | |
| Old Side | city | Pennsylvania | United States | 41.06 | -77.94 | 1669 | |
| Old Stanton | city | Pennsylvania | United States | 40.23 | -79.61 | 997 | |
| Old Sugar Loaf | city | Pennsylvania | United States | 40.96 | -75.97 | 1669 | |
| Old Zionsville | city | Pennsylvania | United States | 40.49 | -75.52 | 830 | |
| Old Zollarsville | city | Pennsylvania | United States | 40.01 | -80.08 | 961 | |
| Olde Kensington | city | Pennsylvania | United States | 39.97 | -75.14 | 39 | |
| Olde Village | city | Pennsylvania | United States | 40.23 | -75.40 | 209 | |
| Oleona | city | Pennsylvania | United States | 41.56 | -77.70 | 1669 | |
| Oleopolis | city | Pennsylvania | United States | 41.46 | -79.62 | 1095 | |
| Oley | city | Pennsylvania | United States | 40.39 | -75.79 | 400 | |
| Oley Furnace | city | Pennsylvania | United States | 40.41 | -75.79 | 830 | |
| Oley Line | city | Pennsylvania | United States | 40.34 | -75.80 | 298 | |
| Oliphant Furnace | city | Pennsylvania | United States | 39.84 | -79.73 | 1669 | |
| Oliveburg | city | Pennsylvania | United States | 40.99 | -79.03 | 1669 | |
| Oliver | city | Pennsylvania | United States | 39.92 | -79.72 | 997 | |
| Oliver Manor | city | Pennsylvania | United States | 41.44 | -79.68 | 1013 | |
| Oliver Mills | city | Pennsylvania | United States | 41.22 | -75.84 | 1669 | |
| Olivet | city | Pennsylvania | United States | 40.59 | -79.41 | 1253 | |
| Olmstead (historical) | city | Pennsylvania | United States | 41.93 | -78.95 | 1669 | |
| Olmsted | city | Pennsylvania | United States | 41.75 | -78.07 | 1669 | |
| Olmsville | city | Pennsylvania | United States | 41.66 | -77.40 | 1794 | |
| Olney | city | Pennsylvania | United States | 40.04 | -75.12 | 101 | |
| Olwen Heights | city | Pennsylvania | United States | 41.36 | -75.55 | 1801 | |
| Olyphant | city | Pennsylvania | United States | 41.47 | -75.60 | 898 |