Largest Counties by Population

Los Angeles

Getty Images / Kenny Hung Photography

by Matt Rosenberg
Matt Rosenberg is a professional geographer and writer with over 20 years of experience. He is the author of both a geography reference book and a guide to winning National Geography Bee contests.
Updated July 28, 2019

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. 

Largest Counties by Population

  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
  30. Cuyahoga County, Ohio: 1,259,828
  31. Orange County, Florida: 1,253,001
  32. Oakland County, Michigan: 1,237,868
  33. Franklin County, Ohio: 1,231,393
  34. Allegheny County, Pennsylvania: 1,231,255
  35. Hennepin County, Minnesota: 1,212,064
  36. Travis County, Texas: 1,151,145
  37. Fairfax County, Virginia: 1,137,538
  38. Contra Costa County, California: 1,111,339
  39. Salt Lake County, Utah: 1,091,742
  40. Montgomery County, Maryland: 1,030,447
  41.  Mecklenburg County, North Carolina: 1,012,539
  42. Pima County, Arizona: 1,004,516
  43.  St. Louis County, Missouri: 1,001,876