US Highway 630: Did it Even Exist?
There are many US Routes that are longer than 1,000 miles in length, which isn't surprising given the size of the United States. Most 3-digit US routes are also relatively long, with the shortest one currently being US Highway 730, between Washington and Oregon, about 40 miles long.
But the shortest in history was another of US-30's children, namely US 630, at just roughly three miles in length, spurring from US 30 in Weiser, ID, and running south over the Snake River into Oregon. This would have made US-630 the shortest route in the entire system by a considerable margin, as US-530, the next shortest US highway ever, was 25 miles long.
Back to 630; this map shows the entirety of the three mile route.
c. 1927, Rand McNally map via USEnds.
Due to its very short lifespan, it is unknown if it was ever signed as such, as it was a predecessor to the much longer US-30N (today known as SPUR US-95).
My personal opinion is that it doesn't matter one way or another if the road was ever signed as such, and at three miles in length for less than a year in service, it's almost certain that no one alive could provide evidence confirming or denying its signing. The fact is the road officially existed, before much more logical heads just simply made it a slightly longer US-30N. That is not to dismiss USEnds' great work in finding this route in the first place, as they are to be thanked for their incredible research that made this blog post possible in the first place. I just liken the route more to an unsigned interstate highway.