| Olds Township | E central Greene County. Named for the Olds family whose members moved there after 1779. |
| Oldwoman Branch | rises in W Pitt County and flows SE into Little Contentnea Creek. |
| Olga | community in W Pender County served by post office, 1900-1908. |
| Olin | town in N central Iredell County. Est. and inc. 1855 as New Institute when Brantley York and Baxter Clegg opened an academy there. Reincorporated 1857 as Olin in honor of Stephen Olin, Methodist educator. Inc. again in 1905, but long inactive in municipal affairs. |
| 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. |