| State: | NM |
| Type: | SR |
| Route: | 166 |
| Map Custom: | yes |
| Map Notes: | NM 166 highlighted in red |
| Length Mi: | 1.9 |
| Length Ref: | [1] |
| Direction A: | West |
| Terminus A: | End of route near Datil |
| Direction B: | East |
| Terminus B: | near Datil |
| Counties: | Socorro |
| Previous Type: | NM |
| Previous Route: | 165 |
| Next Type: | NM |
| Next Route: | 167 |
State Road 166 (NM 166) is a 1.9adj=midNaNadj=mid state highway in Socorro County, New Mexico, United States. NM 166's western terminus is at the end of route east-southeast of Datil, and the eastern terminus is at NM 52 east-southeast of Datil. It runs along a portion of a former alignment of U.S. Route 60 and serves the visitor center of the Very Large Array astronomical observatory.