Most of Irwindale was built recently: 9% of its homes predate 1940 and the median home dates from 1985. Below: maps from 1894 on and the census since 1960.
Founding year: Wikidata. First post office: 1899.The full story ↓
History grade
What drives Irwindale’s History grade
On its age, its old homes and the National Register, Irwindale is more historic than 28% of U.S. towns. Its share of homes from before 1940 holds the grade up; its National Register listings pull it down.
C
HistoryA character grade: shown, never part of Irwindale’s overall grade.
Few California towns list much on the Register (a typical California town has 0.0 per 10,000 residents, the U.S. 2.4), so Irwindale’s 0.0 sits below most of its state (31% of California towns have fewer) while its 0 listings outnumber those of 23% of U.S. towns.
NoteThe founding year comes from Wikidata alone; no second source gives 1860.
How sure. Graded on any two of the three inputs instead, the letter would range from C− to C. The pre-1940 share is a Census survey estimate (±5.2 points).
Founding year: Wikidata (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 Irwindale’s past
Read from the archive, the National Register and the record. The page puts what stands out first.
Irwindale was part of the Mexican land grants by Alta California Governor Juan Alvarado of Rancho La Puente, Rancho Azusa de Dalton, Rancho Azusa de Duarte, and Rancho San Francisquito. The families of Gregorio Fraijo and Facundo Ayon settled here in the 1850s. Significant economic growth did not arrive until the advent of the automobile, which drove up demand for the area's rocks and sand for the paving of roads. The city was incorporated on August 6, 1957.
Irwindale took advantage of urban redevelopment laws starting in 1976, and prospered in the following decade; it attracted a 200-acre (81 ha) Miller Brewing Company plant, the corporate headquarters of Home Savings of America, and other companies.
In 1860, according to Wikidata. Irwindale’s post office opened in 1899, and the census of 1960 counted 1,518 people here.
How does Irwindale rank for history?
Irwindale is more historic than 28% 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 Irwindale?
9% of Irwindale’s homes were built before 1940 (Census estimate, ±5.2 points), against a typical 3.4% for a California town; the median home was built in 1985.
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 (6), 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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