- Old Forge
- Old Fort
- Old Frame
- Old Furnace
- Old Furnace
- Old Gum Tree
- Old Mill Pointe
- Old Mountain House
- Old Orchard
- Old Port
- Old Shade Furnace
- Old Sheffield
- Old Side
- Old Sow Island
- Old Stanton
- Old Sugar Loaf
- Old Zionsville
- Old Zollarsville
- Olde Village
- Oleona
- Oleopolis
- Oley
- Oley Furnace
- Oley Line
- Oliphant Furnace
- Oliveburg
- Oliver
- Oliver Manor
- Oliver Mills
- Olivet