Black Diamond’s post office opened in 1885, and 2 of its places are on the National Register
More historic than 43% of U.S. towns · #82 of 285 in Washington. What drives it
Most of Black Diamond was built recently: 6% of its homes predate 1940 and the median home dates from 2000. Its Register listings are the Black Diamond Cemetery and the Luigi and Aurora Pagani House. Below: 2 old photos and papers, maps from 1912 on, and the census since 1890.
Founding year: the first Black Diamond post office (Blevins & Helbock, CC0).The full story ↓
History grade
What drives Black Diamond’s History grade
On its age, its old homes and the National Register, Black Diamond is more historic than 43% of U.S. towns, #82 of 285 in Washington. Its National Register listings hold the grade up; its share of homes from before 1940 pulls it down.
C+
HistoryA character grade: shown, never part of Black Diamond’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 Black Diamond’s 3.4 sits above most of its state (71% of Washington towns have fewer) while its 2 listings outnumber those of 60% 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 (±3.1 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 Black Diamond’s past
Read from the archive, the National Register and the record. The page puts what stands out first.
Black Diamond was originally inhabited by the Bəqəlšuł, which is Lushootseed for "from a high point from which you can see", part of Coast Salish people. The area was home to a grill trap and smokehouse, and the tribe fished from Lake Sawyer.
Black Diamond was officially incorporated on February 19, 1959. The town's late 20th century population growth has been mostly as a commuter community for people with jobs in Seattle, Bellevue, and suburban centers within the Seattle Metropolitan Area.
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.
Every edition of the U.S. Geological Survey’s map of Black Diamond. Tap a year, or press play to watch the town change.
1949Black Diamond sheet · 1:24,000
U.S. Geological Survey historical topographic maps (public domain), via Esri’s collection of the scans. The red ring marks the center of Black Diamond.
Every building
Black Diamond, building by building, 1912–1929
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.
The Black Diamond post office opened in 1885, the earliest record of the town by name (U.S. post office records).
How does Black Diamond rank for history?
Black Diamond is more historic than 43% of U.S. towns, #82 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 Black Diamond?
Two places: the Black Diamond Cemetery (listed 2000) and the Luigi and Aurora Pagani House (2002).
How old are the homes in Black Diamond?
6% of Black Diamond’s homes were built before 1940 (Census estimate, ±3.1 points), against a typical 4.3% for a Washington town; the median home was built in 2000.
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), the National Register of Historic Places (2), 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.
c. 1915
2011
2009
2009
2004
