The analysis shows that Riverside County had a 52% white, non-Hispanic population in 2000, and a 35% white, non-Hispanic population in 2018 - a change of 17 percentage points.
Orange County went from 52% white, non-Hispanic in 2000 to 40% in 2018 - a change of 12 percentage points.
Ventura County changed 12 percentage points - from 57% in 2000 to 45% in 2018.
Other California counties that saw a change to a non-white majority are Contra Costa, Sacramento, San Diego, San Mateo, Santa Barbara, Stanislaus, Sutter and Yolo.
To view the full report, visit www.pewresearch.org.