| Olin Creek | rises in NW Iredell County and flows SE into Patterson Creek. Formerly known as Little Rocky Creek. |
| Olin Township | N central Iredell County. |
| Olive Branch | community in NE Union County E of Gourdvine Creek. |
| Olive Grove | community in N Cleveland County. |
| Olive Hill | community in central Macon County on Iotla Creek. |
| Olive Hill | community in W Person County. |
| Olive Hill Township | W central Person County. |
| Olive Hollow | W Watauga County, extends northward W of Laurel Creek. |
| Oliver | community in E Johnston County. |
| Oliver Reef | S Dare and E Hyde Counties in the waters of Pamlico Sound N of Hatteras Inlet. Presented by the state to the U.S. government in 1874 for use in naval target practice. Returned to the state in 1965. |