More historic than 4% of U.S. towns · #270 of 285 in Washington. What drives it
Most of Mirrormont was built recently: 0.0% of its homes predate 1940 and the median home dates from 1978. Below: maps from 1953 on and the census since 1990.
On its age, its old homes and the National Register, Mirrormont is more historic than 4% of U.S. towns, #270 of 285 in Washington. Its National Register listings hold the grade up; its share of homes from before 1940 pulls it down.
D−
HistoryA character grade: shown, never part of Mirrormont’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 Mirrormont’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 two of the three inputs, so a change in either one moves the letter more than it would with three. The pre-1940 share (±0.8 points) is firm at this size.
Founding year: our sources. 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 Mirrormont’s past
Read from the archive, the National Register and the record. The page puts what stands out first.
Wikipedia doesn’t have a history of Mirrormont yet. The photos, dates and memories neighbors add here are how it gets written.
Mirrormont is a census-designated place (CDP) in King County, Washington, United States, south of Issaquah. The population was 3,858 at the 2020 census. Within the last decade, the area has seen a shift in development as larger homes have been constructed in Cedar Grove, the Highlands at Tiger Mountain and Mirrormont.
Between the 2010 and 2020 censuses its population grew from 3,659 to 3,858 (+5%).
Intro from Wikipedia. Population: U.S. Census Bureau.
By decade
No old photos in the archives yet
Weddings on Main Street, storms, parades, school pictures, the old store. If it’s in your family album, it belongs here.
Be the first to add onePhotograph a print flat, in daylight, no flash.
Mirrormont is more historic than 4% of U.S. towns, #270 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.
How old are the homes in Mirrormont?
0.0% of Mirrormont’s homes were built before 1940 (Census estimate), against a typical 4.3% for a Washington town; the median home was built in 1978.
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 U.S. Geological Survey historical maps, U.S. Census counts (via Wikipedia) 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.
