The Sullivan Township post office opened in 1845, the earliest record of the town by name. Three smaller post offices, Dunn (1863), Cushman (1872) and Kirksville (1895), opened inside today’s town and later closed.
First census: 528 in 18602020 census: 6,274181 years
How historic is Sullivan Township?
A−
More historic than 84% of U.S. towns, on its age, its old homes and the National Register.
Founding year: the first Sullivan Township post office (Blevins & Helbock, CC0).The full story ↓
History grade
What drives Sullivan Township’s History grade
On its age, its old homes and the National Register, Sullivan Township is more historic than 84% of U.S. towns, #151 of 768 in Illinois. All 3 inputs are above most U.S. towns; its share of homes from before 1940 ranks highest and its National Register listings lowest.
A−
HistoryA character grade: shown, never part of Sullivan 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 Sullivan Township’s 1.6 sits above most of its state (65% of Illinois towns have fewer) while its 1 listings outnumber those of 51% 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 (±5.4 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 Sullivan Township’s past
Read from the archive, the National Register and the record. The page puts what stands out first.
Sullivan was founded in 1845 as Asa's Point. Two years after Sullivan was founded, the first official courthouse of the county was built. It was a simple two-story brick building with a hipped roof, and the county jail was housed in the basement. The village would come alive with gossip when court was in session. Abraham Lincoln passed through this first courthouse many times from 1849 to 1852, as he practiced law in the Moultrie County circuit court. The present courthouse (the county's third) contains a mural depicting this first courthouse.
Every edition of the U.S. Geological Survey’s map of Sullivan Township. Tap a year, or press play to watch the town change.
1935Sullivan 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 Sullivan Township.
On the National Register
1 historic place in Sullivan Township
The country’s official list of buildings and places worth saving.
place listed
1
National Historic Landmarks
0
none yet
historic buildings protected
1
each building in a district counts
National Park Service, National Register of Historic Places. Photos from Wikimedia Commons, credited on each place’s page.
People over time
Sullivan Township, census by census
Between 528 and 4,526 people in every census since 1860.
17 censuses, 1860–2020.
U.S. Census Bureau decennial counts, from the census table on Sullivan Township’s Wikipedia page.
Stories next door
History across the town line
Each neighbor’s History grade, on the same three inputs.
The Sullivan Township post office opened in 1845, the earliest record of the town by name (U.S. post office records).
How does Sullivan Township rank for history?
Sullivan Township is more historic than 84% of U.S. towns, #151 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 Sullivan Township?
27% of Sullivan Township’s homes were built before 1940 (Census estimate, ±5.4 points), against a typical 11% for an Illinois town; the median home was built in 1968.
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 (4), 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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