Arizona edges out Washington on the U.S. Census Bureau’s diversity index. In the 2020 Census, Arizona scored close to the national figure of about 61 percent, while Washington came in a few points lower, in the mid-50s. The two states get there in very different ways: Arizona’s diversity is driven mainly by a large Hispanic population and sizable Native American nations, while Washington’s comes from a broader mix of Asian, Hispanic, Pacific Islander and multiracial residents centered on the Seattle area.
This guide explains how the index works, lays out the numbers side by side, and looks at where each state’s diversity actually shows up, from the Sonoran Desert to Puget Sound.
What the diversity index measures
The Census Bureau’s Diversity Index (DI) is a probability. It tells you the chance that two people chosen at random from a place belong to different racial or ethnic groups. A score of 0 means everyone is in the same group; the closer a score gets to 100, the more likely any two people are to be different.
The groups come from the census race and Hispanic origin questions: Hispanic or Latino, and then non-Hispanic White, Black, Asian, American Indian and Alaska Native, Native Hawaiian and Other Pacific Islander, some other race, and multiracial.
A few caveats are especially relevant to this comparison:
- The index rewards balance. A state with one very large minority group (Arizona’s Hispanic population) and a state with several mid-sized groups (Washington) can end up with fairly similar scores.
- Multiracial residents count as their own group. Washington has one of the higher multiracial shares in the country, which lifts its score.
- Coding changes in the 2020 Census counted more people as multiracial nationwide, so some of the change since 2010 is about measurement, not only migration.
Washington vs Arizona at a glance
The figures below are rounded approximations from recent Census Bureau data. Use them for comparison; the Census Bureau’s tables give exact state and county values.
| Measure | Washington | Arizona |
|---|---|---|
| Population | About 7.8 million | About 7.4 to 7.5 million |
| 2020 diversity index | Mid-50s | Around 60 |
| Hispanic or Latino share | Around 13 to 14 percent | Around 30 percent or more |
| Asian share | Around 9 to 10 percent | Around 3 to 4 percent |
| American Indian and Alaska Native share | Under 2 percent (single race) | Around 4 to 5 percent (single race) |
| Federally recognized tribes | 29 | 22 |
| Main diversity hub | Seattle, King County and South Sound | Phoenix, Tucson and border counties |
The pattern is clear: Arizona has more than twice Washington’s Hispanic share and a much larger Native American population, while Washington has roughly three times Arizona’s Asian share.
Arizona’s diversity up close
Hispanic Arizona
Hispanic heritage in Arizona predates statehood. Tucson was a Spanish presidio in the 1700s and a Mexican town before the Gadsden Purchase made it part of the United States in 1854. Today Mexican Americans make up most of the state’s Hispanic population, and border communities such as Nogales, Douglas and San Luis are overwhelmingly Hispanic. In metro Phoenix, areas such as Maryvale in west Phoenix, Avondale and Tolleson have large Latino majorities.
Tribal nations
Arizona is home to 22 federally recognized tribes, and tribal lands cover roughly a quarter of the state. The Navajo Nation, the largest reservation in the country by area, stretches across northeastern Arizona into Utah and New Mexico. The Tohono O’odham Nation shares a long stretch of the border with Mexico, and the Hopi, Apache, Pima, Maricopa, Yavapai and many other nations have deep ties to the land. Apache County and Navajo County have some of the highest Native American shares of any counties in the United States.
Newer arrivals
Phoenix has become one of the country’s fastest growing metro areas, drawing people from California, the Midwest and abroad. That growth has brought larger Black, Asian and refugee communities, including residents from Iraq, Afghanistan, Somalia, the Democratic Republic of the Congo and Myanmar resettled in Phoenix and Tucson.
Washington’s diversity up close
King County and the South Sound
King County is the heart of Washington’s diversity. Seattle’s Chinatown-International District has long been home to Chinese, Japanese, Filipino and Vietnamese communities. South of the city, Kent, Tukwila, SeaTac, Renton and Federal Way rank among the most diverse places in the Pacific Northwest, with large Somali, Ethiopian, Eritrean, Ukrainian, Mexican, Filipino, Samoan and South Asian populations. Tech employers in Seattle, Bellevue and Redmond have drawn many Indian and Chinese professionals.
Central Washington’s farm country
East of the Cascades, the Yakima Valley and the Columbia Basin have large Mexican American communities tied to orchards, vineyards and food processing. Several counties there, including Franklin, Adams and Yakima, are close to or above half Hispanic, which surprises people who picture Washington as mostly White outside Seattle.
Tribes and Pacific Islanders
Washington has 29 federally recognized tribes, including the Yakama Nation, the Colville Confederated Tribes, the Tulalip Tribes and the Puyallup Tribe. The state also has one of the largest Native Hawaiian and Pacific Islander populations on the mainland, with Samoan, Marshallese, Chamorro and Tongan communities in the Seattle, Tacoma and Spokane areas.
Why Arizona scores slightly higher
The difference is mostly about size. Arizona’s Hispanic population is so large that almost a third of all residents belong to that one group, and when you add a sizable Native American population, the odds of two random people being from different groups rise. Washington’s minority groups are more varied but each is smaller, and its non-Hispanic White share is somewhat higher statewide.
At the local level, though, the picture can flip. Parts of South King County are more diverse than almost anywhere in Arizona, while many rural Arizona counties outside tribal lands are much less diverse than the state average.
What it means in daily life
- Language: Spanish dominates as a second language in Arizona. In Washington, public agencies commonly translate materials into Spanish, Chinese, Vietnamese, Korean, Russian, Ukrainian, Somali and Tagalog.
- Culture and food: Arizona’s Sonoran-style Mexican food and powwows are part of everyday life. Washington’s food scene reflects Pacific Rim influences, from pho and dim sum to East African restaurants in South Seattle.
- Tribal sovereignty: In both states, tribal governments run their own courts, schools, health services and enterprises, and they play a real role in regional economies.
- Growth pressure: Rising housing costs in Seattle and Phoenix push many immigrant and working families into the suburbs, which is one reason diversity is spreading beyond the core cities.
Following local news in each state
Census counts change once a decade, but community life changes constantly. For Washington, Washington PR Daily publishes news and releases from around the state, a practical way to follow businesses, cultural events and community groups from Seattle to Spokane.
In Arizona, Arizona PR Listing covers state news and announcements, useful for keeping up with what organizations and communities are doing in Phoenix, Tucson and beyond.
Whatever the source, look for the dataset (decennial census or American Community Survey), the year, and whether a figure describes a whole state or a specific county or city.
What to watch next
Both states are growing, and both are likely to become more diverse over the next decade. Arizona’s score depends heavily on continued Hispanic growth and migration into Phoenix. Washington’s could rise as its Asian, Hispanic and multiracial populations keep growing. The 2024 federal update to race and ethnicity standards, which merges the race and Hispanic origin questions and adds a Middle Eastern or North African category, will also change how future scores are produced.
Want more pairings? Read California vs Texas for two other large Western and Southwestern states, or Tennessee vs Indiana for a contrast with the heartland. The full series lives in the Daily Bites category.
Frequently asked questions
Is Arizona more diverse than Washington?
Slightly, by the Census Bureau’s measure. Arizona scored around 60 on the 2020 diversity index, while Washington scored in the mid-50s. Arizona’s large Hispanic and Native American populations account for most of the difference.
What is the most diverse area in Washington State?
South King County, including Kent, Tukwila, SeaTac, Renton and Federal Way, is usually ranked as the most diverse part of the state.
How many tribes are in Arizona and Washington?
Arizona has 22 federally recognized tribes and Washington has 29.
Why does Washington have such a large Asian population?
Washington has long-standing Chinese, Japanese and Filipino communities dating back more than a century, and its tech, aerospace and university sectors have attracted many Asian immigrants in recent decades.
Does the diversity index include Native American tribes?
Yes, in the sense that American Indian and Alaska Native is one of the census race groups used in the calculation, but it does not distinguish between individual tribes or nations.
