Black Diamond

County:: King County
County Seat:: No
Area (mi²):: 6.598
State:: Washington

Black Diamond is a city located in King County, Washington. Black Diamond has a 2025 population of 7,772. Black Diamond is currently growing at a rate of 8.14% annually and its population has increased by 60.38% since the most recent census, which recorded a population of 4,846 in 2020.

The average household income in Black Diamond is $172,884 with a poverty rate of 1.14%.The median age in Black Diamond is 38.1 years: 39.9 years for males, and 36.6 years for females.

Demographics

The racial composition of Black Diamond includes 74.66% White, 11.39% Asian, and smaller percentages for other race, Black or African American and multiracial populations.

Population by Race

Race	Population	Percentage (of total)
White	4,239	74.66%
Asian	647	11.39%
Two or more races	620	10.92%
Other race	151	2.66%
Black or African American	21	0.37%

Black Diamond Marital Status

Married

Widowed

Divorced

Separated

Never Married

Economics and Income Statistics

Black Diamond's average per capita income is $86,221. Household income levels show a median of $144,728. The poverty rate stands at 1.14%.

Families: A family includes the owner or renter of the home along with everyone related to them - whether through birth, marriage, or adoption. This includes relatives like spouses, children, parents, siblings, grandparents, and any other family members.

Households: A household includes all the people who occupy a housing unit (such as a house or apartment) as their usual place of residence.

Non Families: A nonfamily household is either someone living alone or when the owner/renter lives with people they aren't related to, like roommates.

Name	Median	Mean
Married Families	$165,855	-
Families	$155,000	$184,640
Households	$144,728	$172,884
Non Families	$86,050	$130,828

$86,221

Average Income

$144,728

Median Household Income

1.14%

Poverty Rate