Largest Counties by Population

Forty-three counties in the United States have a population greater than 1 million, ranked by population. The data for this list is based on mid-2016 population estimates from the United States Census Bureau. In 2010, only 39 counties in the United States had a population of more than 1 million, and Los Angeles County had fewer than 10 million residents. The top five list remains the same as in 2010. 

From this list, you can see that although much of the country's population is concentrated in the megalopolis region of the Northeast, there is considerable population in the metropolitan regions of the Sun Belt from Texas to California. These heavily populated cities of Texas, Arizona, and California continue to experience phenomenal growth as population declines in places like the Rust Belt continue. 

1. Los Angeles County, CA: 10,116,705
2. Cook County, IL: 5,246,456
3. Harris County, TX: 4,441,370
4. Maricopa County, AZ: 4,087,191
5. San Diego County, California: 3,263,431
6. Orange County, California: 3,145,515
7. Miami-Dade County, Florida: 2,662,874
8. Kings County, New York: 2,621,793
9. Dallas County, Texas: 2,518,638
10. Riverside County, California: 2,329,271
11. Queens County, New York: 2,321,580
12. San Bernardino County, California: 2,112,619
13. King County, Washington: 2,079,967
14. Clark County, Nevada: 2,069,681
15. Tarrant County, Texas: 1,945,360
16. Santa Clara County, California: 1,894,605
17. Broward County, Florida: 1,869,235
18. Bexar County, Texas: 1,855,866
19. Wayne County, Michigan: 1,764,804
20. New York County, New York: 1,636,268
21. Alameda County, California: 1,610,921
22. Middlesex County, Massachusetts: 1,570,315
23. Philadelphia County, Pennsylvania: 1,560,297
24. Suffolk County, New York: 1,502,968
25. Sacramento County, California: 1,482,026
26. Bronx County, New York: 1,438,159
27. Palm Beach County, Florida: 1,397,710
28. Nassau County, New York: 1,358,627
29. Hillsborough County, Florida: 1,316,298