<US 650 | Home | US 666 >
| US 660 renumbered | |||||
| Previous US 660's: |
US 660: Created in 1926 when AASHO approved a 6th branch off of US 60. Because this was east of the 5th branch - US 560 from US 60 Gallup NM to US 450 Cortez CO, AASHO made this new branch US 560 and renumbered the US 560 from the 1925 plan to US 660. When the US 60-66 swap occurred, US 660 was renumbered as US 666. Today it is the US 491 corridor.
The 1926 New Mexico documents from the AASHO database have a single reference to 660, but in a way that made it seem like it could have been a typo, since they also didn't mention 560 moving to the new branch. However, the March 2003 New Mexico application to renumber US 666 had a summation of the entire history of that corridor and had this passage:
 2003 application to AASHTO There is a preliminary AASHO map that shows the corridor as US 560 with 666 handwritten on it, as well as the 1926 Colorado official map showing it as US 560. However, I found a map that did label it US 660.
| ||||
Previous: US 650 | Next: US 666
US 60 | US 160 | US 260 | US 360 | US 460 | US 560
Page last modified 10 February 2026