Most of Oso was built recently: 0.0% of its homes predate 1940 and the median home dates from 2000. Below: 2 old photos and papers, maps from 1956 on, and the census since 2000.
The Oso post office opened in 1890, the earliest record of the town by name. Another post office, Allen (1889), opened inside today’s town and later closed.
First census: 246 in 20002020 census: 172136 years
Founding year: the first Oso post office (Blevins & Helbock, CC0).The full story ↓
What stands out about Oso’s past
Read from the archive, the National Register and the record. The page puts what stands out first.
The town was originally named Allen, but was renamed to Oso to avoid confusion with Allyn in Mason County. Oso is Spanish for bear and was named by J. P. Britzius after the town of Oso, Texas in Fayette County. The Texas town no longer exists, having been abandoned in favor of the nearby town of Flatonia which had a railway station.
On Saturday, March 22, 2014, at 10:37 a.m. local time, a major mudflow occurred 4 miles (6.4 km) east of Oso, when a portion of an unstable hill collapsed, sending mud and debris across the North Fork of the Stillaguamish River, engulfing a rural neighborhood, and covering an area of approximately 1 square mile (2.6 km2). Forty-three people were killed.
Passages that mention Oso, cut from the printed page as they were published.
History of Snohomish County, Washington, Volume I1926 · page 336Read the page →
Read the text
Oso was employed to conduct a four months’ term of school, and the chief business events of the month were the purchase of the steamship Idaho as a freighter out of Everett ; the proposal to bridge the Snohomish River at the foot of Everett Avenue, and the reported retirement of Henry Hewitt, Jr., from the presidency of the Everett Land Co., to be succeeded by J. Weymss of West Superior, Wis. This proved but a rumor, but it was the first public intimation that all was not harmonious within the ranks of the promoters.
Text read by machine from the scan; it may contain errors.
History of Snohomish County, Washington, Volume I1926 · page 519Read the page →
Read the text
worth now lives, and carried fruit trees on his back from Stanwood to his claim, thirty-five miles away. He was a soldier in the Army of the Potomac, and is now in the Washington Soldiers’ Home at Orting. The same year J. H. Armstrong took the claim that is now the townsite of Oso, and John D. Wilson, another bachelor, located his present place. Three years later Mrs. Jessie Wilson and her three girls came, and like prudent and practical people, they each proved up a homestead.
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.
Timeline
Oso, 1889 to 1956
Woven from the archive, old maps, post office records, the National Register and the people born 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.
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). How TownRatings grades history →
From Wikimedia Commons (6), 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 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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