Least racially diverse, US counties · 2020
US counties with the lowest CensusEasy Diversity Score, where most residents share the same race or ethnicity (2023 ACS). Petroleum County, Montana leads at 3. 3,135 counties qualify in total. Kentucky carries 7 of the top 25 entries.
Flip the list · Most racially diverse, US counties →UPDATED 2026-06-02 · DATA: US CENSUS BUREAU ACS 5-YEAR ESTIMATES
Frequently asked
Which county has the lowest diversity score?
Petroleum County, Montana ranks #1 with 3 (2020 American Community Survey).
What are the top 5 counties by diversity score?
Petroleum County, Montana, McPherson County, Nebraska, Garfield County, Montana, Magoffin County, Kentucky, Robertson County, Kentucky.
How many counties are in this ranking?
3,135 counties qualify after filtering for population minimums and data availability. The ranking covers 2020 ACS 5-year data.
How is diversity score measured?
CensusEasy Diversity Score (0 to 100): the chance that two random residents are of a different race or ethnicity, rescaled so 100 is a perfectly even split across all five groups. A Simpson diversity index over the five ACS race and ethnicity shares. Source: US Census Bureau, American Community Survey 5-year estimates (2020).