I can’t think of any highway in Indiana that has been bypassed and/or moved more that US 31. Part of this, honestly, was because the original route left something to be desired when it came to turns, curves and other hazards. Keeping in mind that US 31 came into being on 1 October 1926, there were a lot of changes before the coming of 1946, its twentieth anniversary.
At Columbus, it changed quite a bit over the years. At one point, there was a US 31 and a US 31A, an extended following of the old Madison State Road, a take over of both SR 9 and SR 9W, and a removal and replacement of a section of SR 7 (which would later become part of SR 46!).
Let’s start with the original US 31, as marked on 1 October 1926. Coming from the north, US 31 followed the old Madison State Road, and the Jackson Highway Auto Trail, into Columbus along what is now Indianapolis Road to its junction at 8th Street (yes, I know, that intersection is gone). The road then turned south on Brown Street to Second Street, where the bridge crossed the Flatrock River. US 31 then exited Columbus on what is now SR 11.
The first change in the routing of US 31 happened in the time frame of 1940-1941 (as shown in the 1941 Indiana Official Map), when the road was routed, from Second and Brown Streets, along SR 7 to the junction that, in 1939, was listed as SR 9W. That routing is the current path from what is now SR 46 south to Seymour. (SR 46 was rerouted over a decade ago to take over what was SR 9.) In 1939, there was SR 9W, which ran south from SR 7 to Bartholomew County Road 475S. At that time, CR 475S was SR 9, which then turned south on what is now US 31 (National Road). National Road would be the same as CR 400E. Old US 31 became US 31A with the moving of the official US 31 route. The 1941 map also shows that the current bypass from north of Columbus to SR 7 was under construction.
As a side note, I mentioned that the original US 31 entered Columbus from the north on the original Indianapolis-Madison State Road. That old road left Columbus along what is shown on these maps as SR 7. Now, it would be SR 46 before it becomes SR 7.
The 1942 official map shows that the US 31 bypass of Columbus was complete. With this completion, not only was SR 9 removed south of Columbus (replaced by US 31), it was rerouted to the road that is now SR 46. At Newbern, SR 46 and SR 9 met for 70 years. INDOT would move SR 46 to the route of SR 9 south of that point, ending SR 9 at the same place.
The 1979 official map shows something that I don’t remember ever seeing before: SR 31A. What was US 31A is marked on the 1979 as SR 31A. This makes sense, given the way Indiana does state road numbers. There have been very few “A” routes in Indiana history. Usually, if a bypass is built, Indiana gives the old route a “daughter” number. It was unusual that this route was given an “A” number, even more so that it remained officially a US route for 36 years. In 1983, the road would again be labelled, on maps anyway, as US 31A.
The last official change made to US 31 in the Columbus area was in 1985, when the old US 31A was recommissioned as SR 11. This made the old road a continuation of SR 11 which connected at the end of US 31A at Seymour.
1999 would be the last year that the old US 31 leaving Columbus to the north would be part of the state highway system. In 2000, not only was that section of SR 11 removed, but SR 46 was rerouted along what was SR 9, and SR 7 ended at US 31. That would end 82 years of Indianapolis Road in Columbus being a state road. It all started by being part of State Market Highway 1 in 1917. Then original SR 1 in 1919.