Founding year: Wikidata; Wikipedia’s history section gives the same year. First post office: 1892.The full story ↓
History grade
What drives Zillah’s History grade
On its age, its old homes and the National Register, Zillah is more historic than 61% of U.S. towns, #43 of 285 in Washington. Its National Register listings hold the grade up; its age pulls it down.
B
HistoryA character grade: shown, never part of Zillah’s overall grade.
Few Washington towns list much on the Register (a typical Washington town has 0.1 per 10,000 residents, the U.S. 2.4), so Zillah’s 6.4 sits above most of its state (79% of Washington towns have fewer) while its 2 historic buildings outnumber those of 60% of U.S. towns.
How sure. Graded on any two of the three inputs instead, the letter would range from B− to B+. The pre-1940 share is a Census survey estimate (±7.2 points). Two sources give 1891.
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 Zillah’s past
Read from the archive, the National Register and the record. The page puts what stands out first.
Zillah was founded in 1891 following the completion of the Sunnyside Canal project, an irrigation scheme delivering water from the Yakima River to the arid lower Yakima Valley. Walter Granger, superintendent of the canal company, chose the town site in 1892. The town was named for Zillah Oakes, daughter of Northern Pacific Railway president Thomas Fletcher Oakes, who had financed the canal's construction. She was the youngest member of an expedition to scout possible townsites; allegedly, the town was named for Zillah after she had fallen into a stream with the party's wagon and had to be consoled by her father. Granger housed the headquarters of the Washington Irrigation Company in Zillah, giving it economical advantages for a time. He also made his residency in Zillah, becoming its mayor after retiring from the irrigation company. Zillah was officially incorporated on January 5, 1911.
In 1891, according to Wikidata and Wikipedia’s history of the town. Zillah’s post office opened in 1892, and the census of 1920 counted 647 people here.
How does Zillah rank for history?
Zillah is more historic than 61% of U.S. towns, #43 of 285 in Washington. 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.
What is on the National Register in Zillah?
One place: the Teapot Dome Service Station (listed 1985).
How old are the homes in Zillah?
16% of Zillah’s homes were built before 1940 (Census estimate, ±7.2 points), against a typical 4.3% for a Washington town; the median home was built in 1979.
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), Wikidata (1), the National Register of Historic Places (1), Wikipedia, 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 and Sanborn fire insurance maps (Library of Congress). Archive images are copied here with their credits and licenses, shown on each photo’s page. Refreshed monthly.
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