Founding year: the first Castle Rock post office (Blevins & Helbock, CC0).The full story ↓
History grade
What drives Castle Rock’s History grade
On its age, its old homes and the National Register, Castle Rock is more historic than 43% 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 Castle Rock’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 Castle Rock’s 0.0 sits below most of its state (27% of Washington 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 (±9.5 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 Castle Rock’s past
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.
Castle Rock is named for a volcanic rock outcropping over the Cowlitz River, "The Rock", rising 190 feet high on the south side of the city. The rock formation, resembling a castle, became a geographic landmark for Cowlitz Indians and Hudson's Bay Company traders as early as 1832. Today, it is the location of The Rock Community Park, with hiking trails, picnic tables, and a historical marker.
Nothing in the archives for these yearsWeddings on Main Street, storms, parades, school pictures, the old store. If it’s in your family album, it belongs here.
Nothing in the archives for these yearsWeddings on Main Street, storms, parades, school pictures, the old store. If it’s in your family album, it belongs here.
Grew from 681 people in 1890 to 2,446 in 2020, 3 times over.
14 censuses, 1890–2020.
U.S. Census Bureau decennial counts, from the census table on Castle Rock’s Wikipedia page.
Questions about Castle Rock’s history
What year was Castle Rock founded?
The Castle Rock post office opened in 1854, the earliest record of the town by name (U.S. post office records).
How does Castle Rock rank for history?
Castle Rock is more historic than 43% 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 Castle Rock?
23% of Castle Rock’s homes were built before 1940 (Census estimate, ±9.5 points), against a typical 4.3% for a Washington town; the median home was built in 1970.
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), the Library of Congress (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 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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