Ten years ago, after the 2010 U.S. census data on race and ethnicity was released, a Seattle Times analysis found that Seattle was one of the “whitest” big cities in the country. At the time, 66% of Seattle’s population was white, fifth highest among the 50 most populous U.S. cities.

The recently released 2020 census data shows that 59.5% of the city’s population is white. Because of that decline, we no longer rank fifth for white population.

We now rank — hold onto your hats — sixth.

Admittedly, that’s not a huge difference. Even so, it is one indicator that Seattle diversified at a faster pace than most other big cities over the past decade.

For this column, I calculated a “diversity index” score for major U.S. cities using both the 2020 and 2010 census racial/ethnic data. The index score measures how likely it is that two people who live in the same place, chosen at random, would be of a different race/ethnicity. The higher the score, the more diverse the place is. A low score means most residents are of the same race/ethnicity.


Seattle’s diversity index score for 2020 was 60.1. Among the 50 largest U.S. cities, Seattle ranked as the 39th most racially diverse (or 12th least diverse, depending on your point of view) in 2020.

You might read that and think, comparatively, Seattle isn’t terribly diverse.

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But look at it this way. Back in 2010, Seattle’s diversity index score was just 52.9. So over the course of the decade, Seattle’s score increased by more than 7 points. Among the 50 most populous U.S. cities, we tied with Baltimore for having the fifth-largest increase in racial diversity.

While Seattle’s white and Black populations had relatively slower growth in the past decade, the city’s multiracial, Hispanic and Asian populations all grew dramatically. The Native American and Pacific Islander populations, which were already fairly small, shrank a little.


Portland, which is less racially diverse than Seattle, had a slightly larger increase in its diversity index score, and ranks fourth. While the Rose City has diversified over the past decade, it remains the “whitest” large U.S. city, at around 66% white.

Tulsa, Oklahoma, and Indianapolis tied for having the biggest increase in their diversity index scores, both at 8 points, with Detroit in third place. The Motor City, which is majority Black, was the least racially diverse big city in 2010. Since then, its Black population has shrunk dramatically while its white and Asian populations have increased a bit. Because of that population shift, Detroit was no longer the least racially diverse city in 2020. That distinction goes to El Paso, Texas, which is about 81% Hispanic (its index score was 32.4).

To calculate the index, I used the Census Bureau’s racial categories (white, Black, Asian, Native American/Alaska Native, Pacific Islander/Native Hawaiian, multiracial, and some other race) plus Hispanic ethnicity. I treated Hispanic as a racial category, in line with American cultural perceptions (the Census Bureau, though, considers Hispanic as an ethnicity distinct from racial identity).

It should also be noted that these racial/ethnic categories are very broad, encompassing people of many different backgrounds. Within each of these categories there exists a tremendous amount of cultural diversity.

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Some cities were already so diverse in 2010 that it would be impossible for their score to increase very much. Oakland, California, ranked as the most diverse big city in 2020 with a score of 77.1. Sacramento, California, and New York City round out the top three, in that order.

Of the 50 largest cities, 27 do not have a single racial/ethnic group that makes up the majority of the population. Seattle, of course, is one of the 23 that does.

As readers of this column probably already know, Seattle is less racially diverse than many other parts of King County. The diversification process was already well underway in South King County in the 1990s. On the Eastside, Bellevue began to grow more diverse in the 2000s.

In fact, Bellevue already had a higher diversity index score than Seattle in 2010, at 56.8. The score jumped 7 points to hit 63.8 in 2020. Unlike Seattle, Bellevue does not have a single racial/ethnic group in the majority. White people are the largest group, at 43.5% of the total population in the 2020 census.