Good news! I was wrong … mostly.
On the page for IA 39, I said that present-day US 30 west of the west edge of Denison, following the railroad, was never part of the Lincoln Highway. Well, in the course of exhaustive research since I wrote that — see the Denison Highway Chronology — a correction is needed.
The original Lincoln Highway to Dow City stayed on the north side of the then-Chicago & North Western Railroad and Illinois Central Railroad. This included stairsteps through Arion that every source does differently. In the second half of 1925, IA 6 was graded on an alignment paralleling the railroads on the south side. The Denison Review on Nov. 10, 1926, said the C&NW overpass was completed. The state map was not updated until after paving through Crawford County was completed in 1929.
In 1960, US 30 was four-laned from Denison to the northeast corner of Dow City. In 1962, a relocation of US 30 over the railroad and Boyer River was completed. Chamberlin Drive is a piece of the 1925-62 route of 30.
It’s possible that the 1929 Lincoln Highway pavement, and very likely the 1925 bridges, stayed in place until one of those bridges near Dow City had to be closed because it couldn’t handle semis. That probably happened Oct. 28, 1980, based on articles in the Review on Oct. 25, 1980, and July 9, 1981. The concrete on the closed segment was extant at least through April 1982, according to aerial photos.
About a mile and a half of westbound 30 from the intersection southwest of the ethanol plant to Chamberlin Drive is on the roadbed of the Lincoln Highway built in 1925.
So there you have it. After it took a decade for me to update the IA 39 page (2008-18), it took another five years to correct a supplemental part.