On its age, its old homes and the National Register, South Ottawa Township is more historic than 79% of U.S. towns, #188 of 768 in Illinois. All 3 inputs are above most U.S. towns; its age ranks highest and its National Register listings lowest.
A−
HistoryA character grade: shown, never part of South Ottawa 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 South Ottawa Township’s 1.2 sits near the middle of its state (63% of Illinois towns have fewer) while its 1 listings outnumber those of 51% of U.S. towns.
NoteThe founding year comes from Wikidata alone; no second source gives 1849.
How sure. Graded on any two of the three inputs instead, the letter would range from B+ to A−. The pre-1940 share is a Census survey estimate (±5.0 points).
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 South Ottawa 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 South Ottawa Township. Tap a year, or press play to watch the town change.
1892Ottawa 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 South Ottawa Township.
The story so far
South Ottawa Township, in brief
Wikipedia doesn’t have a history of South Ottawa Township yet. The photos, dates and memories neighbors add here are how it gets written.
South Ottawa Township is located in LaSalle County, Illinois. As of the 2020 census, its population was 8,343 and it contained 3,812 housing units.
South Ottawa Township was established in 1849. Its population held steady between the last two censuses: 8,290 in 2010, 8,343 in 2020.
Intro from Wikipedia. Population: U.S. Census Bureau.
South Ottawa Township is more historic than 79% of U.S. towns, #188 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 South Ottawa Township?
20% of South Ottawa Township’s homes were built before 1940 (Census estimate, ±5.0 points), against a typical 11% for an Illinois town; the median home was built in 1960.
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 (2), U.S. Geological Survey historical maps 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.
2026
2026
