| Onslow Court House | See Jacksonville. |
| Onvil | community in central Montgomery County near the head of Thickety Creek. Served by post office, 1883-1915. |
| Onward | community in SW Montgomery County served by post office, 1887-96. |
| Ooneroy | a Tuscarora Indian village on the Roanoke River in Bertie County shown on the Moseley map, 1733. It was a chief town of the Tuscarora; the name meant "gathered together." |
| Open Branch | rises in N Jackson County and flows NW into Hornbuckle Creek. |
| Open Land | or a shrub bog area of approx. 50,000 acres in Carteret County about 12 mi. NE of Beaufort. An attempt to reclaim the area in 1926 was abandoned, but much of it is now included in a large experimental farm. |
| Open Ridge | S Yancey County between Rock Creek and South Toe River. |
| Opening, The | a clay and swamp area in E Pitt County between the head of Clayroot Swamp and Chicod Creek. |
| Ophir | community in N Montgomery County served by post office, 1883-1933. Settled shortly after the middle of the nineteenth century in the midst of a gold-producing area and named for the land furnishing gold for King Solomon's Temple in biblical days. Now an agricultural and timber-producing community. |
| Ophir Township | NW Montgomery County. |