Each edition grades its towns against each other only.
More historic than 84% of U.S. towns · #260 of 1,035 in Pennsylvania. What drives it
Its Register listing is the Brush Hill. Below: 10 old photos and papers, maps from 1884 on, and the census since 1820.
Irwin first appears in the census in 1820.
More historic than 84% of U.S. towns, on its age, its old homes and the National Register.
On its age, its old homes and the National Register, Irwin is more historic than 84% of U.S. towns, #260 of 1,035 in Pennsylvania. All 3 inputs are above most U.S. towns; its share of homes from before 1940 ranks highest and its National Register listings lowest.
Pennsylvania towns list about as much on the Register as the country (a typical Pennsylvania town has 2.1 per 10,000 residents, the U.S. 2.4), so Irwin’s 2.6 sits near the middle of its state (60% of Pennsylvania towns have fewer) while its 1 listings outnumber those of 51% of U.S. towns.
Founding year: the first census (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 →
Read from the archive, the National Register and the record. The page puts what stands out first.
Fire insurance maps drew every building, what it was made of and what it was used for, so insurers could price the risk of fire. Pick a year, then a sheet.
1884Sheet 1 of 2Sanborn Map Company, via the Library of Congress. Editions published in 1930 or earlier, which are in the public domain.
Every edition of the U.S. Geological Survey’s map of Irwin. Tap a year, or press play to watch the town change.
U.S. Geological Survey historical topographic maps (public domain), via Esri’s collection of the scans. The red ring marks the center of Irwin.
From Wikipedia’s history of Irwin.
Irwin was named for John Irwin, the original owner of the town site.
Irwin was the original western terminus of the Pennsylvania Turnpike when it opened in October 1940.
Brush Hill was listed on the National Register of Historic Places in 1975.
Text from Wikipedia, licensed CC BY-SA 4.0.
Passages that mention Irwin, cut from the printed page as they were published.
and there engaged in the livery business and stock raising. After a residence of three years in that state he moved to Missouri, near Kansas City, and there followed farming and the raising of fine stock. He then returned to Pennsylvania and settled on the Michael Clohessy farm, near Irwin, remaining four years. The following two years he engaged in the feed business in Irwin, after which he purchased his present farm, which is located in the vicinity of Irwin and consists of sixty-seven acres of productive land. The stone dwelling thereon is nearly a hundred years old. Mr. Painter is a
Text read by machine from the scan; it may contain errors.
three years he was the oldest fireman on the Pittsburg division, one of which was spent on construction train work. He received his promotion to the post of engineer, December 26, 1898, running on a coal train from Irwin to Derry. His present run is a day passenger from Irwin to Greensburg by the way of Youghiogheny and Hempfield branches. He is also interested in the real estate business in Irwin and in Pitcairn, in the latter place having an interest in the firm of Shultz & Enyeart, dry goods and groceries, and interested in the Superior White Oak Lumber Company. Mr. Snively is a member of the IMetho-
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.
Woven from the archive, old maps, post office records, the National Register and the people born here.
In the archiveIrwin, Pennsylvania 1897
On the mapFirst mapped by the U.S. Geological Survey
In the archiveIrwin PA 1st Presby PHS279
In the archiveTicket offices at the west end of the Turnpike, at Irwin, Pa., view of the Turnpike on a …
In the archiveMinsky Brothers & Co. PA121 (1B-H348) Airplane View of Interchange at Junction of Pennsyl…
Born hereMark Critz is born here4 decades in the archive, from the 1890s to the 1940s. Scroll each row; tap a photo for its story.
No then-and-now pairs yet. Take a photo from the same spot as an old one and they appear here side by side.
Find the spot, match the angle, and add your photo. It becomes the first then-and-now pair on Irwin’s page.
Retake this view · +15The country’s official list of buildings and places worth saving.
National Park Service, National Register of Historic Places. Photos from Wikimedia Commons, credited on each place’s page.
Between 405 and 4,995 people in every census since 1820.
17 censuses, 1820–2020.
U.S. Census Bureau decennial counts, from the census table on Irwin’s Wikipedia page.
Writers, athletes, leaders and more, ranked by how widely they’re known.
Irwin’s post office has been open since 1884.
US Post Offices dataset (Blevins & Helbock, CC0). Places and cemeteries from the USGS Geographic Names Information System (2021).
Most archives stop around 1920. The photos from after that are in family albums, not libraries.
The Irwin post office opened in 1820, the earliest record of the town by name (U.S. post office records). Wikidata gives 1853.
Irwin is more historic than 84% of U.S. towns, #260 of 1,035 in Pennsylvania. 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.
One place: the Brush Hill (listed 1975).
30% of Irwin’s homes were built before 1940 (Census estimate, ±8.2 points), against a typical 18% for a Pennsylvania town; the median home was built in 1954.
What the archives can’t tell you, neighbors can.
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 (18), the National Register of Historic Places (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), the USGS Geographic Names Information System, Sanborn fire insurance maps (Library of Congress) 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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