More historic than 18% of U.S. towns · #650 of 768 in Illinois. What drives it
Most of Clarendon Hills was built recently: 3% of its homes predate 1940 and the median home dates from 1982. Below: 2 old photos and papers, maps from 1891 on, and the census since 1880.
Founding year: the first Clarendon Hills post office (Blevins & Helbock, CC0). Wikidata: 1924.The full story ↓
History grade
What drives Clarendon Hills’ History grade
On its age, its old homes and the National Register, Clarendon Hills is more historic than 18% of U.S. towns, #650 of 768 in Illinois. Its age holds the grade up; its share of homes from before 1940 pulls it down.
C−
HistoryA character grade: shown, never part of Clarendon Hills’ 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 Clarendon Hills’ 0.0 sits below most of its state (28% of Illinois towns have fewer) while its 0 listings outnumber those of 23% of U.S. towns.
How sure. Graded on any two of the three inputs instead, the letter would range from D to C−. The pre-1940 share (±1.5 points) is firm at this size. The founding year is the first post office, not a stated founding date; Wikidata gives 1924.
Founding year: the first post office (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 Clarendon Hills’ 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 Clarendon Hills. Tap a year, or press play to watch the town change.
1891Riverside 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 Clarendon Hills.
The area that is now Clarendon Hills was a wide, rolling prairie bordering the east side of Westmont. Most of the older villages in Downers Grove Township were built on the same street grid as the Village of Downers Grove. Instead, Clarendon Hills was built to resemble nearby Riverside, a planned, park-like suburb designed by Fredrick Law Olmsted in the late 1800s. Its long winding streets go with the natural contour of the land, rather than extending straight through from the neighboring towns. In 1923, at the time of incorporation, Clarendon Hills had a population of under 900 people. The area was incorporated to avoid annexation by the nearby community of Hinsdale.
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.
The Clarendon Hills post office opened in 1874, the earliest record of the town by name (U.S. post office records). Wikidata gives 1924.
How does Clarendon Hills rank for history?
Clarendon Hills is more historic than 18% of U.S. towns, #650 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 Clarendon Hills?
3% of Clarendon Hills’ homes were built before 1940 (Census estimate, ±1.5 points), against a typical 11% for an Illinois town; the median home was built in 1982.
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 (5), the Library of Congress (1), Wikipedia, Wikidata and Wikipedia for famous people, 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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2016