During the late 1930s and early 1940s, a plan was implemented to expand US 40, aka the National Road, to a four lane divided highway across the entire state. There are places along the old route that had to be bypassed for safety reasons. The section between Knightstown and Dunreith was just such a place.
But the road wasn’t the only thing moved in this case.
A 1910 map of the area shows the old National Road, and its original alignment, between Knightstown and Dunreith. This section shows one of the few places in Indiana where the original Terre Haute & Richmond Railroad (actually, the Terre Haute & Indianapolis [west] and the Indiana Central [east] when they were finally built) crossed the National Road. The shallow angle crossing at Dunreith would be a thorn in the side of the Indiana State Highway Commission since it took over the old road in 1917 (as OSR 3).
Fast forward to 1939. The ISHC has started moving and widening US 40 east from the east side of Knightstown to Dunreith. By 2 August 1939, five miles of new road had been graded and was ready for paving. For anyone that has been there, they will notice that US 40 curves to the northeast, with an access road created to connect to the Old National Road (see next map).
A sharp-eyed individual will notice that you can draw a straight line across the Big Blue River connecting the two sections of the National Road. This matches the above map, which shows the old road as a straight line.
What takes some investigation in the whole project is that the new bridge over the Big Blue River is in the wrong place. Or, more to the point, the old crossing and the new crossing are in two different places. It’s a river. Exactly what happened that the old bridge couldn’t be replaced in place?
Going back to the Greenfield Daily Reporter of 2 August 1939, there is a news story that covers this exact question. The ISHC moved the Big Blue River “Several Hundred Feet East of Knightstown.” That’s right…the whole river was moved to the east.
From what I can see, the old river bed would have been right about where the curve started in the bypass of US 40. With this, the moving of the Big Blue River makes sense.
This also shows the difference between then and now. This project would be next to impossible to pull off today. There would be a ton of environmental hoops to jump through to get this done. And, honestly, I am not quite sure such a project would be worth it.
The other end of this bypass, at Dunreith,
removed the dangerous crossing of the Pennsylvania Railroad mainline from Pittsburgh to St. Louis. This is not the first time that US 40 had been moved because of the PRR. It also occurred east of Plainfield.
This bypass opened in 1940, not only making a four lane divided highway between Knightstown and Dunreith, it eliminated two crossings of the PRR: the dangerous crossing at Dunrieth, and a narrow underpass at the Knightstown end. The underpass in question was a slight reroute of the PRR through the area, and is a typical PRR-type construction. Both crossings would be moot 40+ years later when the railroad was abandoned in favor of the “Bee” Line to Crestline, OH.
In the end, US 40 was built as the typical 1940’s ISHC divided highway: two traffic lanes, wider shoulder, and a wide median. Examples of this kind of construction appear all over the state. But very few required the moving of a river.