Gwinnett County Went From 91% White to 30%: The Most Diverse Counties in America

In 1990, Gwinnett County, Georgia was 91.1 percent white. It was a fast-growing but overwhelmingly homogeneous stretch of Atlanta suburb, the kind of place that showed up in the census as a rounding error away from monolithic. Today it is the fourth most diverse county in the United States, and no racial or ethnic group holds even a third of the population. Almost nothing about American demographic change is as dramatic as what happened in that one county in 35 years.

We measure it with the CensusEasy Diversity Score, a 0 to 100 index built on the chance that two residents picked at random are of a different race or ethnicity, using the five Census Bureau race and ethnicity shares. A score near 100 means an almost perfectly even split. The full method is on our methodology page.

The most diverse counties in America

Queens tops the list, which will surprise nobody who has ridden the 7 train. The rest of the leaders are mostly large suburban counties attached to big metros: Fort Bend outside Houston, Montgomery outside Washington, Prince William in northern Virginia, and a cluster of California counties. The one oddity is Aleutians West in Alaska, a place of about 5,200 people whose seafood-processing workforce draws from around the world, producing a genuinely mixed population at a very small scale.

How Gwinnett County flipped

What makes Gwinnett remarkable is not just that it is diverse, but how recently it was not. Here is the same county, measured the same way, in 1990 and today.

In 1990 one group held more than nine in ten residents. Today the county's four largest groups sit at roughly 31, 28, 24, and 13 percent. That near-even four-way split is precisely what drives a diversity score of 94.1: the index rewards balance, not merely the presence of a minority population. Very few places of any size in America have arrived at a distribution this level.

The growth that carried it

The transformation was not a case of one population replacing another. Gwinnett nearly tripled in size while it changed, which means the county absorbed newcomers rather than swapping them.

Gwinnett added more than 665,000 people in 35 years and crossed a million residents. Through the 1990s and 2000s it was one of the fastest-growing counties in the country, and the growth arrived from everywhere at once: Black families moving from Atlanta and from the North, Latin American immigration along the Buford Highway corridor, and South Asian and East Asian communities that built the county's now-extensive commercial districts. The white population did not collapse in absolute terms; it was simply outpaced, several times over, by everyone else arriving.

More than a quarter of Gwinnett was born abroad

The engine behind the shift is immigration. An estimated 28.4 percent of Gwinnett residents were born outside the United States, up from 25.5 percent in 2010, and 20.3 percent speak Spanish at home. In a county of a million people, that is more than 280,000 foreign-born residents, a share higher than Georgia as a whole by a wide margin.

The detailed origin data shows how many distinct communities sit underneath the four broad race categories. Roughly 100,300 residents report Mexican origin, 49,100 Central American, and 37,600 South American. About 42,600 report Sub-Saharan African ancestry and 30,200 West Indian. On the Asian side, roughly 30,500 are Indian, 27,700 Korean, and 25,100 Vietnamese. These counts come from different census questions covering Hispanic origin, detailed Asian origin, and ancestry, so they overlap and do not sum to the county total, but together they map a county where a dozen sizable communities live side by side.

Diverse, fairly integrated, and affluent

Two things complicate the easy assumptions people bring to a story like this. The first is that diversity at the county level can hide segregation at the neighborhood level. It does not much here. Gwinnett scores 33.2 on our segregation index, which measures how unevenly white and non-white residents are spread across the county's census tracts on a 0 to 100 scale. That sits at the low end of the moderate range, and it has fallen from 35.7 in 2020, meaning the mixing is happening block by block, not just in the countywide totals.

The second is the assumption that a diversifying suburb must be a declining one. Gwinnett's median household income is $87,890, above both Georgia's $77,353 and the national figure of $82,259. Its median home value of $380,900 tops the state's $303,300, and 39.0 percent of adults hold a bachelor's degree against 34.9 percent statewide. The county got more diverse and more prosperous at the same time.

Why suburbs, not cities, top this list

The counties at the top of this ranking share a profile. They are suburban, they are attached to large job markets, and they grew fast enough over the past three decades to be reshaped by immigration and domestic migration at the same time. The old mental model, in which the city is diverse and the suburbs are homogeneous, is now backwards in much of the country. Gwinnett, Fort Bend, Prince William, and Montgomery are all suburban counties that became more mixed than the cities they orbit.

It is the same statewide shift we traced in how Georgia is diversifying, and the inverse of the places losing diversity we covered in which cities have become less diverse since 2000. See the full ranking of all 3,144 counties at most diverse counties, the city version in the most diverse cities in America, or explore Gwinnett County's full data profile and the wider Atlanta metro.

Sources

The Diversity Score is a CensusEasy original index, a Simpson diversity index over the five race and ethnicity shares rescaled from 0 to 100, documented on our methodology page. Race, ethnicity, and population figures are from the U.S. Census Bureau American Community Survey and the 1990 decennial census, with the 2025 population from the Census Bureau's Population Estimates Program. Full ranking: most diverse counties.