O'Fallon Township dates to 1854, and 2 of its places are on the National Register
More historic than 60% of U.S. towns · #328 of 768 in Illinois. What drives it
Most of O'Fallon Township was built recently: 7% of its homes predate 1940 and the median home dates from 1992. Below: 6 old photos and papers, maps from 1907 on, and the census since 1870.
Founding year: Wikidata. First post office: 1827.The full story ↓
History grade
What drives O'Fallon Township’s History grade
On its age, its old homes and the National Register, O'Fallon Township is more historic than 60% of U.S. towns, #328 of 768 in Illinois. Its National Register listings hold the grade up; its age pulls it down.
B
HistoryA character grade: shown, never part of O'Fallon Township’s overall grade.
Few Illinois towns list much on the Register (a typical Illinois town has 0.5 per 10,000 residents, the U.S. 2.4), so O'Fallon Township’s 54.5 sits above most of its state (91% of Illinois towns have fewer) while its 146 historic buildings outnumber those of 91% of U.S. towns.
NoteThe founding year comes from Wikidata alone; no second source gives 1854.
How sure. Graded on any two of the three inputs instead, the letter would range from C to B+. The pre-1940 share (±1.9 points) is firm at this size.
Founding year: Wikidata (other dates in Quick answers). Homes: Census ACS 2020–24. National Register: National Park Service, May 2026 list; each listing counted once (boundary changes and added documentation belong to their listing), and a historic district counts its contributing buildings. How TownRatings grades history →
What stands out about O'Fallon Township’s past
Read from the archive, the National Register and the record. The page puts what stands out first.
Every edition of the U.S. Geological Survey’s map of O'Fallon Township. Tap a year, or press play to watch the town change.
1907Belleville sheet · 1:62,500
U.S. Geological Survey historical topographic maps (public domain), via Esri’s collection of the scans. The red ring marks the center of O'Fallon Township.
Founded in 1854, O'Fallon's namesake comes from Colonel John O'Fallon who was a wealthy gentleman from St. Louis. In downtown O'Fallon, a Baltimore and Ohio Railroad railroad depot was built, which helped put O'Fallon on the map. City lots were platted and sold at a public auction on May 18, 1854. A post office was established the following year and the city began attracting German settlers looking for fertile farming land. On January 27, 1874, O'Fallon was incorporated as a village. On March 14, 1905, the citizens voted for a change to the city form of government. Since its founding, O'Fallon has gained population every decennial census year except 1930, when the census showed a net loss of six residents.
Nothing in the archives for these yearsWeddings on Main Street, storms, parades, school pictures, the old store. If it’s in your family album, it belongs here.
Nothing in the archives for these yearsWeddings on Main Street, storms, parades, school pictures, the old store. If it’s in your family album, it belongs here.
In 1854, according to Wikidata. O'Fallon Township’s post office opened in 1827, and the census of 1870 counted 1,117 people here.
How does O'Fallon Township rank for history?
O'Fallon Township is more historic than 60% of U.S. towns, #328 of 768 in Illinois. The History grade combines the town’s founding era, the share of homes built before 1940 and its National Register listings. It’s a character grade, so it isn’t part of the overall grade. How it works.
How old are the homes in O'Fallon Township?
7% of O'Fallon Township’s homes were built before 1940 (Census estimate, ±1.9 points), against a typical 11% for an Illinois town; the median home was built in 1992.
Founding dates: Wikidata, Wikipedia, the U.S. post office records of Blevins & Helbock (CC0) and the Census. Homes by year built: Census ACS 2020–24. National Register of Historic Places: National Park Service (list of May 22, 2026). Old photos, postcards and papers: Wikimedia Commons, the Library of Congress and other public archives, credited on each item’s page. Maps: U.S. Geological Survey historical topographic maps (via Esri) and Sanborn fire-insurance maps (Library of Congress). History text and census tables: Wikipedia (CC BY-SA 4.0). Places that used to be: USGS Geographic Names Information System (2021).
From Wikimedia Commons (6), Wikipedia, U.S. Geological Survey historical maps, U.S. Census counts (via Wikipedia), the US Post Offices dataset (Blevins & Helbock) and the USGS Geographic Names Information System. Archive images are copied here with their credits and licenses, shown on each photo’s page. Refreshed monthly.
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