Founding year: the first Mazon Township post office (Blevins & Helbock, CC0).
History grade
What drives Mazon Township’s History grade
On its age, its old homes and the National Register, Mazon Township is more historic than 63% of U.S. towns. Its age holds the grade up; its National Register listings pull it down.
B
HistoryA character grade: shown, never part of Mazon 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 Mazon Township’s 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 B− to A−. The pre-1940 share is a Census survey estimate (±4.8 points). The founding year is the first post office, not a stated founding date.
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 Mazon Township’s past
Read from the archive, the National Register and the record. The page puts what stands out first.
Wikipedia doesn’t have a history of Mazon Township yet. The photos, dates and memories neighbors add here are how it gets written.
Mazon (məˈzɒn/) is a village in Mazon Township, Grundy County, Illinois, United States. The name derives from the Potawatomi word for "nettles" (mzan). The population was 979 at the 2020 census. Illinois' State Fossil, the unique and bizarre Tully Monster was first found in nearby Mazon Creek. Mazon was formerly served by the Santa Fe railway at the Mazon Depot. It was established in 1876.
Its first post office opened in 1837. Its population held steady between the last two censuses: 1,487 in 2010, 1,503 in 2020.
Intro from Wikipedia. Population: U.S. Census Bureau.
From the old history books
What they wrote about Mazon Township, 1882–1914
Passages that mention Mazon Township, cut from the printed page as they were published.
Historical encyclopedia of Illinois /cedited by Newton Bateman, Paul Selby,1914Read the page →
Read the text
There is no doubt hut that the first schoolhouse of Mazon Township was built in 1837 on Section 24. At that time it was regarded as the finest schoolhouse in the surrounding country and the best cabin in the settlement.
Text read by machine from the scan; it may contain errors.
Historical encyclopedia of Illinois /cedited by Newton Bateman, Paul Selby,1914Read the page →
Read the text
1829, a sen of Gersham and Annie Ishani. The family came to Mazon Township, Grundy County in 1S44, and there Michael Ishani became the owner of eighty acres of land. After operating it for some years, he located in the village of Mazon and embarked in a mercantile business.
Text read by machine from the scan; it may contain errors.
History of Grundy County, Illinois1882 · page 71Read the page →
Read the text
the township of Waupousee. He has since sold this and bought 213 acres of cultivated land located iu Section 5, of Goodfarm Township, and Section 32, of Mazon Township, valued at $50 per acre. He owns two lots and a handsome residence in the village of Mazon.
Text read by machine from the scan; it may contain errors.
Scans and text from the Internet Archive. Books published in 1930 or earlier, which are in the public domain.
Every edition of the U.S. Geological Survey’s map of Mazon Township. Tap a year, or press play to watch the town change.
1950Dwight 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 Mazon Township.
People over time
Mazon Township, census by census
Between 442 and 1,015 people in every census since 1900.
13 censuses, 1900–2020.
U.S. Census Bureau decennial counts, from the census table on Mazon Township’s Wikipedia page.
Places that used to be
Places now gone and burying grounds
Gone or out of use
Gibson SchoolschoolJ B Fillman Airportairport
4cemeteries and burying grounds inside Mazon Township
BrooksideOld MazonWardWheeler
Places and cemeteries from the USGS Geographic Names Information System (2021).
Stories next door
History across the town line
Each neighbor’s History grade, on the same three inputs.
The Mazon Township post office opened in 1837, the earliest record of the town by name (U.S. post office records).
How does Mazon Township rank for history?
Mazon Township is more historic than 63% of U.S. towns. 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 Mazon Township?
20% of Mazon Township’s homes were built before 1940 (Census estimate, ±4.8 points), against a typical 11% for an Illinois town; the median home was built in 1977.
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), U.S. Geological Survey historical maps, U.S. Census counts (via Wikipedia), the USGS Geographic Names Information System and old county and town histories (Internet Archive). Archive images are copied here with their credits and licenses, shown on each photo’s page. Refreshed monthly.
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