The title of the marker, “How Correctionville Got It’s Name!” is both enthusiastic and mispunctuated. It’s “its” not “it’s”.
Correctionville, in Woodbury County, is named for the survey correction line that runs through the town and across the state. The offset in the county lines is related to this line. Another offset runs on the Muscatine-Cedar county line above the southern tier of the counties to the west.
At various points in its history, US 20 has followed significant portions of the line across the state. Segments from Dyersville to Raymond, the Black Hawk-Grundy county line to IA 14, Williams to Duncombe, and Early to the east edge of Sioux City hewed on or closely to the line.
With the construction of four-lane roads, though, new segments often stray from the grid, either slightly or running on the half-section. Much of new 20 from Early to Moorland will be about a mile and a half south of the correction line; new 20 in Grundy County is half a mile off.
US 20 in Woodbury County carries both varieties of this highway evolution. West of Moville it was moved on to the grid, four miles through Moville have always been half a mile off, and from east of Moville to east of Correctionville it was moved off of the grid. Then, at L37, it returns to the grid to run along the east-west portion of the Woodbury-Ida line.
The segment west of Correctionville is the one with the newest construction plans out. The DOT plans to move much of entire four-lane road just a smidge north, removing the current two-lane in favor of building a 21st-century roadbed. It also moves the right-of-way acquisition mostly to the north side. The PDF map available online shows the new four-lane gently weaving through or beside the half-section grid line.
For more information, here’s a story from KTIV last week.