North Dakota Highway 91 (Pembina County) should not be confused with North Dakota Highway 91 (Wells County).
| State: | ND |
| Type: | ND |
| Route: | 91 |
| Length Mi: | 1.262 |
| Length Round: | 3 |
| Map Custom: | yes |
| Direction A: | South |
| Terminus A: | in St. Thomas |
| Direction B: | North |
| Terminus B: | in St. Thomas |
| Counties: | Pembina |
| Previous Type: | ND |
| Previous Route: | 89 |
| Next Type: | ND |
| Next Route: | 97 |
North Dakota Highway 91 (ND 91) is a 1.262adj=midNaNadj=mid north–south state highway in the U.S. state of North Dakota. ND 91's southern terminus is at U.S. Route 81 (US 81) in St. Thomas, and the northern terminus is at US 81 in St. Thomas.[1]