The Riley Township post office opened in 1849, the earliest record of the town by name. Two smaller post offices, Riley (1849) and South Riley (1874), opened inside today’s town and later closed.
2020 census: 3,035177 years
How historic is Riley Township?
B−
More historic than 55% of U.S. towns, on its age, its old homes and the National Register.
Founding year: the first Riley Township post office (Blevins & Helbock, CC0).
History grade
What drives Riley Township’s History grade
On its age, its old homes and the National Register, Riley Township is more historic than 55% of U.S. towns, #366 of 768 in Illinois. Its age holds the grade up; its National Register listings pull it down.
B−
HistoryA character grade: shown, never part of Riley 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 Riley 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 C+ to B+. The pre-1940 share is a Census survey estimate (±8.8 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 Riley 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 Riley Township yet. The photos, dates and memories neighbors add here are how it gets written.
Riley is an unincorporated community and census-designated place in McHenry County, Illinois, United States. It was named a CDP before the 2020 census, at which time it had a population of 10.
Its first post office opened in 1849. Between the 2010 and 2020 censuses its population grew from 2,922 to 3,035 (+4%).
Intro from Wikipedia. Population: U.S. Census Bureau.
From the old history books
What they wrote about Riley Township, 1885–1922
Passages that mention Riley Township, cut from the printed page as they were published.
History of McHenry County, Illinois1922 · page 379Read the page →
Read the text
In the southwestern part of the county is found the civil township of Coral, which comprises all of congressional township 43, range 6, east, hence is six miles square. It is south of Seneca Township, west of Grafton Township, north of Kane County, and east of Riley Township. Its soil is fertile and especially well adapted for dairy purposes. The territory is well watered by Kiswaukee Creek and its small tributaries.
Text read by machine from the scan; it may contain errors.
History of McHenry County, Illinois1885 · page 931Read the page →
Read the text
Whitman Cobb, formerly from Cazenovia County, N. Y., settled here in the fall of 1836. A few years afterward he moved to Jo Daviess County, where he remained several years and then returned to Riley Township, this county, where he died Feb. 2, 1866. Ephraim Rogers came from Rutland County, Yt., and settled here in the fall of 1836 and died Nov. 6, 1867.
Text read by machine from the scan; it may contain errors.
History of McHenry County, Illinois1922 · page 119Read the page →
Read the text
were held. In all this vast region there was not a single church house at that date, private homes being made into '•meeting houses." In the autumn of 1837, Rev. William Gaddis preached his firsl sermon at the house of Dr. Eli Smith, in Riley Township. The audience did not i sceed eight persons besides the doctor's family. Sometime in 1838 the minister in charge funned a class at .Marengo, holding meetings in the house of Calvin Spencer. Tin' following were the firsl members of the [limner society: Eli Smith, elassdeader ; Asenith Smith. Samuel and
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.
By decade
No old photos in the archives yet
Weddings on Main Street, storms, parades, school pictures, the old store. If it’s in your family album, it belongs here.
Be the first to add onePhotograph a print flat, in daylight, no flash.
Every edition of the U.S. Geological Survey’s map of Riley Township. Tap a year, or press play to watch the town change.
1938Genoa 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 Riley Township.
Famous people
Famous people close to Riley Township
Nobody well known was born in Riley Township itself, so here are the best known from just nearby.
The Riley Township post office opened in 1849, the earliest record of the town by name (U.S. post office records).
How does Riley Township rank for history?
Riley Township is more historic than 55% of U.S. towns, #366 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 Riley Township?
14% of Riley Township’s homes were built before 1940 (Census estimate, ±8.8 points), against a typical 11% for an Illinois town; the median home was built in 1991.
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 U.S. Geological Survey historical maps, the US Post Offices dataset (Blevins & Helbock), 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.
