In 1920, Iowa was the 16th-largest state in the country by population. That population was as distributed as it was ever going to be, as many rural counties had peaked in population 20 years earlier and were already starting to decline.
As such, the primary route network, then and now, had a lot of the same ideas for community connections. But there are some noticeable holes in what we have now vs. what was marked in 1920. Aside from the interstates and four-lane roads, of course, these links tend to fall in broad groups.
- Two major diagonals, IA 60 and IA 330, came later. The former followed the Chicago, St. Paul, Minneapolis and Omaha Railway; the latter was a brand-new line that set off fierce debate in the Legislature.
- Long, straight or mostly-straight roads that go significant distances with few/very small towns along them.
- The most glaring case is Cherokee to Pocahontas, which didn’t become a state highway for 20 years!
- Nearly the entire routes of IA 21, IA 143, IA 188, and IA 281, and all of IA 182 and IA 346
- Nearly the entire route of IA 15 (Rolfe to Armstrong), excluding the northernmost and southernmost portions
- The north half of IA 146
- IA 17 north of IA 3
- IA 1 north of Iowa City, even though it follows the path of the original Military Road
- IA 92 west of US 71
- US 59 between Ida Grove and Denison, which seems odd because it connects two bordering county seats
- IA 3 between Strawberry Point and Luxemburg
- The Fayette County portion of IA 93
- US 59 south of US 34
- US 65 south of US 34
- IA 25 south of US 34
- IA 148 north of US 34 (notice a lot of these are in south-central or southwest Iowa)
- All of the above segments combined put around two dozen towns lacking a state road on one or within a couple miles.
- Maybe-not-quite-as-straight roads that connect little towns along a railroad line.
- The most obvious, following both a railroad and a river, is the 1920 lack of a “river road” between Dubuque and Clinton. A Davenport-Muscatine road along the river would be added in 1924.
- All or nearly all of IA 16, IA 22, IA 24, IA 26, IA 78, IA 183 (post-2003 version), IA 191 (post-2003 version), and IA 210. IA 49 would have fit here.
- IA 175 from the Missouri River to Onawa, Turin to Mapleton, Lohrville to Gowrie, and Dayton to Hubbard
- IA 141 from Sloan to Smithland, Manilla to Manning, Coon Rapids to Perry, and Woodward to Camp Dodge (the four-lane to Grimes came later)
- IA 38 north of IA 64
- The north half of IA 48 (Red Oak to Griswold)
- IA 4 south of Jefferson
- IA 83 from Walnut to Atlantic
- IA 136 between Wyoming and US 61
- Neither IA 37 east of Dunlap nor the north-south portion of 136 follow any particular railroad, but they sure aren’t straight either.
With the exception of a few short pieces and three longer ones, all of the roads listed above had become part of the state highway system by 1940. The long segments that came later were IA 188 between Plainfield and Clarksville (1949), IA 346 between the Little Brown Church and US 63 (1953), and IA 21 north of IA 8 (1969). The last was the last all-new two-lane road built for Iowa’s highway system (although it was planned as four). Already-existing county roads were incorporated into IA 21, 210, and 281 (1980) and IA 330 between Albion and US 30 (1989).
The last 30 years have been spent on expressways and freeways. The significant relocations of US 20 through Iowa River Greenbelt and between Early and Moorland are the biggest ones you can point at from a high-level view and say there weren’t any roads near them before.