Black Diamond, Washington Demographics & Population 2026
During the 2020–2024 ACS period, Black Diamond, Washington had a total population of 5,961, the 183rd largest city in Washington, with a median household income of $141,383, which is 44% higher than the state average. The poverty rate is 2.1%.
Data vintage: U.S. Census Bureau ACS 2020–2024 5-Year Estimates · refreshed July 2026 · Methodology & source notes
Key Takeaways
- Household income is 44% above the state average — one of the wealthiest communities in Washington.
- An exceptionally low poverty rate of 2.1% — among the lowest in Washington.
- 54.7% of adults hold a bachelor's degree or higher — top 10% in Washington.
- Near full employment with an unemployment rate of just 1.3%.
Black Diamond Quick Facts
How Black Diamond Changed
Change from the 2019–2023 ACS period to 2020–2024. These are rolling five-year estimates, not year-over-year measurements.
| Metric | 2019–2023 | 2020–2024 | Change |
|---|---|---|---|
| Population | 5,678 | 5,961 | +5.0% |
| Median household income | $144,728 | $141,383 | -2.3% |
| Median home value | $776,400 | $779,100 | +0.3% |
How Black Diamond Compares
Median Household Income
Median Home Value
Economy & Housing
Household Income Distribution
Detailed income brackets
Employment
Housing Overview
People & Demographics
Age Distribution
Race & Ethnicity
Diversity Index
Moderate diversity with one or two groups making up the majority.
State average: 56 | National average: 61
Education
Educational Attainment (Adults 25+)
Black Diamond Rankings in Washington
Explore Washington Rankings
Other Cities in King County
| City | Population | Median Income | Poverty | Home Value |
|---|---|---|---|---|
| Seattle | 754,195 | $123,860 | 9.9% | $938,600 |
| Bellevue | 151,847 | $165,576 | 7.2% | $1,340,300 |
| Kent | 135,603 | $92,302 | 10.8% | $587,800 |
| Renton | 105,317 | $100,432 | 8.1% | $672,600 |
| Federal Way | 99,493 | $86,909 | 13.0% | $552,800 |
| Kirkland | 92,621 | $150,414 | 6.1% | $1,115,400 |
| Auburn | 85,676 | $97,884 | 8.9% | $547,900 |
| Redmond | 77,353 | $162,560 | 5.6% | $1,167,800 |
| Sammamish | 66,463 | $239,690 | 4.3% | $1,407,300 |
| Shoreline | 61,431 | $112,751 | 8.8% | $811,100 |
Cities Similar to Black Diamond
These cities in the same state have comparable population and economic profiles.
| City | Population | Median Income | Home Value | Bachelor's+ | Poverty |
|---|---|---|---|---|---|
| Maplewood | 5,803 | $135,943 | $708,300 | 53.6% | 5.6% |
| Manchester | 5,956 | $126,371 | $478,200 | 32.4% | 11.9% |
| Brier | 6,545 | $132,045 | $866,600 | 50.6% | 6.7% |
| Hockinson | 6,150 | $113,295 | $722,200 | 39.4% | 3.2% |
| Wollochet | 6,689 | $149,271 | $889,900 | 55.8% | 1.5% |
Population Overview
Black Diamond is a small city located in Washington, within King County. The total population is 5,961. It ranks as the 183rd most populous out of 628 Census-designated places in Washington.
Age Demographics
The median age in Black Diamond is 38.1 years. This is about the same as the state median of 38.3 years.
Economy, Income & Housing
The median household income in Black Diamond is $141,383. This is 44% higher than the state median of $98,141. It is also 75% higher than the national median of $80,734. The poverty rate stands at 2.1%. This is 79% lower than the state poverty rate of 9.9%. This exceptionally low poverty rate indicates strong economic prosperity across the community. The unemployment rate is 1.3%. This is 74% lower than the state rate of 5.1%. The median home value is $779,100. Housing costs are 38% higher than the state median of $564,600. The home-value-to-income ratio is 5.5x. 86.0% of occupied housing units are owner-occupied. This homeownership rate is 35% higher than the state average of 63.8%.
Race & Ethnicity
The largest racial or ethnic group in Black Diamond is White (non-Hispanic), making up 67.0% of the population. Asian residents account for 17.6%. The Black or African American population (0.4%) is well below the state average of 3.9%. The Asian population is significantly higher than the state average (17.6% vs 9.7%).
Education
54.7% of residents aged 25 and older hold a bachelor's degree or higher. This places Black Diamond in the top 10% of all cities in the state for educational attainment. This is 38% higher than the state rate of 39.6%. Nationally, 35.7% of adults hold at least a bachelor's degree. The high school graduation rate (or equivalent) is 97.7%. Notably, 17.9% of adults hold a graduate or professional degree, indicating a highly educated workforce.
Data Sources & Methodology
All demographic data for Black Diamond, Washington is sourced from the U.S. Census Bureau's American Community Survey (ACS) 2020–2024 5-Year Estimates. The ACS collects data from approximately 3.5 million households annually and pools five years of responses so that even small communities can be measured, though the margin of error widens as the population falls. Comparisons are made against Washington state averages and national averages calculated from the same dataset. Rankings reflect the city's position among all 628 Census-designated places in Washington. Read more about how these figures are produced on our methodology page, or visit data.census.gov for official data.
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Frequently Asked Questions
What is the population of Black Diamond, Washington?
Black Diamond, Washington has a population of 5,961 according to the most recent U.S. Census ACS 5-Year Estimates.
What is the median household income in Black Diamond, WA?
The median household income in Black Diamond is $141,383, which is 75% higher than the national median of $80,734.
What is the poverty rate in Black Diamond, WA?
The poverty rate in Black Diamond is 2.1%. This means approximately 125 residents live below the federal poverty line.
What is the racial makeup of Black Diamond, Washington?
Black Diamond's population is 67.0% White, 0.4% Black, 7.9% Hispanic/Latino, and 17.6% Asian.
What is the median home value in Black Diamond, WA?
The median home value in Black Diamond is $779,100. The home-value-to-income ratio is 5.5x.
How educated is Black Diamond, Washington?
54.7% of adults (25+) in Black Diamond hold a bachelor's degree or higher, and 17.9% hold a graduate or professional degree.