Clearlake Oaks’ post office opened in 1935
More historic than 8% of U.S. towns. What drives it
Most of Clearlake Oaks was built recently: 2% of its homes predate 1940 and the median home dates from 1975.
How Clearlake Oaks began
When was Clearlake Oaks founded?
The Clearlake Oaks post office opened in 1935, the earliest record of the town by name. Another post office, Stubbs (1926), opened inside today’s town and later closed.
How historic is Clearlake Oaks?
More historic than 8% of U.S. towns, on its age, its old homes and the National Register.
What drives Clearlake Oaks’ History grade
On its age, its old homes and the National Register, Clearlake Oaks is more historic than 8% of U.S. towns. Its National Register listings hold the grade up; its age pulls it down.
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 Clearlake Oaks’ 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.
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 →
Lost post offices and old corners
Clearlake Oaks’s post office has been open since 1935. Another post office, Stubbs, opened and closed inside today’s town.
US Post Offices dataset (Blevins & Helbock, CC0). Places and cemeteries from the USGS Geographic Names Information System (2021).
Questions about Clearlake Oaks’ history
What year was Clearlake Oaks founded?
The Clearlake Oaks post office opened in 1935, the earliest record of the town by name (U.S. post office records).
How does Clearlake Oaks rank for history?
Clearlake Oaks is more historic than 8% 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 Clearlake Oaks?
2% of Clearlake Oaks’ homes were built before 1940 (Census estimate, ±2.9 points), against a typical 3.4% for a California town; the median home was built in 1975.
Memory lane
What the archives can’t tell you, neighbors can.
Where this page comes from
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 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.