US 630 was 23 miles long

[Mapmikey]

A close reading of the 1927 AASHO documentation reveals that when they asked Idaho if their initial US route descriptions were correct, Idaho replied in March 1927 that US 95 ended at US 630 Weiser and that US 630 ended at US 30 Ontario Junction, which is adjacent to Fruitland.  Idaho also in that first March 1927 reply requested 630 be renumbered as 30N which occurred in May 1927.

Note that a separate document sent to AASHO in March 1927 also said 630 ended at Ontario Junction. 

The 1924-26 Idaho Biennial Highway Report also had a December 1926 state map that showed this:


At least one commercial map showed this as well: Rumsey

IMO it is still unlikely 630 was posted, though...

[The Ghostbuster]

That was the first US 630. The second one was nearby, at only two miles long: https://www.usends.com/630.html. While US 130-830 were all once in commission, only 130 and 730 still exist.

[Mapmikey]

That was the first US 630. The second one was nearby, at only two miles long: https://www.usends.com/630.html. While US 130-830 were all once in commission, only 130 and 730 still exist.

The first US 630 was in the 1925 plan and was in Utah.

The second US 630 replaced US 320 in July 1926 and was 3 miles long until Idaho informed AASHO that 630 ran further than that.