Special Report

America's Largest Counties

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Here is an indication of how the population of the United States is spread out over the 48 contiguous states, Alaska, and Hawaii. There are 3,070 counties in the U.S. yet  only 44 of them have a population of more than 1 million. 

Of those 44 counties with populations exceeding 1 million, nine are in California, the most populous state. The biggest county in the country by population is Los Angeles County, which includes the city of Los Angeles, the nation’s second-biggest city. (These are the 50 largest cities in America.)

To determine America’s 50 largest counties, 24/7 Wall St. reviewed five-year population data from the U.S. Census Bureau’s 2019 American Community Survey, ranking counties by population. For each county we also collected land and total area in square miles, also from the Census Bureau, and calculated population density.

 Though New York state is the fourth most populous, it has seven counties on the list — six of them with a population greater than 1 million. And it is probably not surprising that four of them make up most of New York City — Queens, Kings, the Bronx, and New York counties. These four New York counties also have the four highest population densities of all counties.

Texas and Florida, the second and third most populous states, have six counties on the list each.

Population size in these counties is also driven by economic opportunity, and many of the counties on this list are also among the most affluent in their respective states, such as Arizona’s Maricopa County, Santa Clara County in California, North Carolina’s Wake County, and Honolulu in Hawaii. In Fairfax County in Northern Virginia and Montgomery County in Maryland, both the population and household income have grown because of their proximity to Washington, D.C. (This is every state’s best county to live in.)

Not surprisingly, many of these counties are home to some of the nation’s largest cities. Fulton County in Georgia is home to Atlanta. The city of Dallas is in Dallas County in Texas. And you’ll find Salt Lake City in Salt County in Utah. 

Some counties dominate their state in population. Two out of every three Nevada residents live in Clark County — home to Las Vegas — with a population of 2,182,004.

These are America’s largest counties

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50. Pinellas, Florida
> Population: 964,666
> Total area (including water) in square miles: 607.7 — 1,711 highest
> Land area square miles: 279.9 — 2,848 highest
> Population density: 3,426 — 30 highest

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49. Westchester, New York
> Population: 968,890
> Total area (including water) in square miles: 500.1 — 2,178 highest
> Land area square miles: 432.8 — 2,347 highest
> Population density: 2,321 — 55 highest

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48. Collin, Texas
> Population: 973,977
> Total area (including water) in square miles: 885.9 — 1,005 highest
> Land area square miles: 847.6 — 986 highest
> Population density: 1,256 — 123 highest

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47. Fresno, California
> Population: 984,521
> Total area (including water) in square miles: 6,017.4 — 63 highest
> Land area square miles: 5,962.7 — 59 highest
> Population density: 169 — 613 highest

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46. Honolulu, Hawaii
> Population: 984,821
> Total area (including water) in square miles: 2,126.8 — 291 highest
> Land area square miles: 599.8 — 1,626 highest
> Population density: 1,695 — 84 highest

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45. St. Louis, Missouri
> Population: 996,919
> Total area (including water) in square miles: 523.7 — 2,089 highest
> Land area square miles: 507.8 — 2,046 highest
> Population density: 1,977 — 71 highest

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44. Pima, Arizona
> Population: 1,027,207
> Total area (including water) in square miles: 9,188.8 — 34 highest
> Land area square miles: 9,186.3 — 27 highest
> Population density: 114 — 803 highest

43. Fulton, Georgia
> Population: 1,036,200
> Total area (including water) in square miles: 534.6 — 2,054 highest
> Land area square miles: 528.7 — 1,980 highest
> Population density: 2,018 — 68 highest

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42. Montgomery, Maryland
> Population: 1,043,530
> Total area (including water) in square miles: 507.1 — 2,143 highest
> Land area square miles: 495.5 — 2,104 highest
> Population density: 2,143 — 61 highest

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41. Wake, North Carolina
> Population: 1,069,079
> Total area (including water) in square miles: 857.3 — 1,070 highest
> Land area square miles: 831.9 — 1,011 highest
> Population density: 1,358 — 113 highest

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40. Mecklenburg, North Carolina
> Population: 1,074,475
> Total area (including water) in square miles: 546.2 — 2,013 highest
> Land area square miles: 526.3 — 1,988 highest
> Population density: 2,120 — 63 highest

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39. Salt Lake, Utah
> Population: 1,133,646
> Total area (including water) in square miles: 807.8 — 1,153 highest
> Land area square miles: 737.4 — 1,198 highest
> Population density: 1,607 — 92 highest

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38. Contra Costa, California
> Population: 1,142,251
> Total area (including water) in square miles: 802.1 — 1,167 highest
> Land area square miles: 720.0 — 1,244 highest
> Population density: 1,619 — 88 highest

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37. Fairfax, Virginia
> Population: 1,145,862
> Total area (including water) in square miles: 406.6 — 2,562 highest
> Land area square miles: 395.0 — 2,550 highest
> Population density: 2,912 — 38 highest

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36. Allegheny, Pennsylvania
> Population: 1,221,744
> Total area (including water) in square miles: 744.7 — 1,284 highest
> Land area square miles: 730.2 — 1,210 highest
> Population density: 1,713 — 82 highest

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35. Travis, Texas
> Population: 1,226,805
> Total area (including water) in square miles: 1,022.1 — 740 highest
> Land area square miles: 989.3 — 692 highest
> Population density: 1,304 — 119 highest

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34. Hennepin, Minnesota
> Population: 1,245,837
> Total area (including water) in square miles: 606.4 — 1,715 highest
> Land area square miles: 556.6 — 1,868 highest
> Population density: 2,302 — 56 highest

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33. Cuyahoga, Ohio
> Population: 1,247,451
> Total area (including water) in square miles: 1,245.6 — 553 highest
> Land area square miles: 458.5 — 2,235 highest
> Population density: 2,759 — 43 highest

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32. Oakland, Michigan
> Population: 1,253,185
> Total area (including water) in square miles: 908.0 — 926 highest
> Land area square miles: 872.5 — 934 highest
> Population density: 1,461 — 101 highest

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31. Franklin, Ohio
> Population: 1,290,360
> Total area (including water) in square miles: 543.3 — 2,022 highest
> Land area square miles: 539.9 — 1,936 highest
> Population density: 2,452 — 50 highest

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30. Orange, Florida
> Population: 1,349,746
> Total area (including water) in square miles: 1,004.2 — 761 highest
> Land area square miles: 907.5 — 828 highest
> Population density: 1,576 — 96 highest

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29. Nassau, New York
> Population: 1,356,509
> Total area (including water) in square miles: 453.1 — 2,326 highest
> Land area square miles: 286.7 — 2,827 highest
> Population density: 4,869 — 19 highest

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28. Hillsborough, Florida
> Population: 1,422,278
> Total area (including water) in square miles: 1,266.2 — 544 highest
> Land area square miles: 1,050.9 — 620 highest
> Population density: 1,389 — 110 highest

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27. Bronx, New York
> Population: 1,435,068
> Total area (including water) in square miles: 57.4 — 3,102 highest
> Land area square miles: 42.0 — 3,104 highest
> Population density: 35,038 — 3 highest

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26. Palm Beach, Florida
> Population: 1,465,027
> Total area (including water) in square miles: 2,386.3 — 247 highest
> Land area square miles: 1,974.1 — 285 highest
> Population density: 756 — 192 highest

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25. Suffolk, New York
> Population: 1,483,832
> Total area (including water) in square miles: 2,373.1 — 249 highest
> Land area square miles: 912.2 — 816 highest
> Population density: 1,673 — 85 highest

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24. Sacramento, California
> Population: 1,524,553
> Total area (including water) in square miles: 995.5 — 772 highest
> Land area square miles: 965.7 — 723 highest
> Population density: 1,641 — 86 highest

Source: Sean Pavone / Getty Images

23. Philadelphia, Pennsylvania
> Population: 1,579,075
> Total area (including water) in square miles: 142.6 — 3,074 highest
> Land area square miles: 135.1 — 3,063 highest
> Population density: 11,872 — 8 highest

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22. Middlesex, Massachusetts
> Population: 1,600,842
> Total area (including water) in square miles: 847.5 — 1,084 highest
> Land area square miles: 823.5 — 1,026 highest
> Population density: 1,982 — 70 highest

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21. New York, New York
> Population: 1,631,993
> Total area (including water) in square miles: 33.8 — 3,109 highest
> Land area square miles: 23.0 — 3,108 highest
> Population density: 73,791 — 1 highest

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20. Alameda, California
> Population: 1,656,754
> Total area (including water) in square miles: 821.2 — 1,126 highest
> Land area square miles: 737.6 — 1,197 highest
> Population density: 2,281 — 57 highest

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19. Wayne, Michigan
> Population: 1,757,299
> Total area (including water) in square miles: 672.2 — 1,510 highest
> Land area square miles: 614.1 — 1,575 highest
> Population density: 2,920 — 37 highest

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18. Broward, Florida
> Population: 1,926,205
> Total area (including water) in square miles: 1,319.6 — 510 highest
> Land area square miles: 1,205.4 — 505 highest
> Population density: 1,613 — 90 highest

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17. Santa Clara, California
> Population: 1,927,470
> Total area (including water) in square miles: 1,304.0 — 518 highest
> Land area square miles: 1,290.7 — 460 highest
> Population density: 1,500 — 99 highest

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16. Bexar, Texas
> Population: 1,952,843
> Total area (including water) in square miles: 1,256.7 — 548 highest
> Land area square miles: 1,246.8 — 484 highest
> Population density: 1,612 — 91 highest

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15. Tarrant, Texas
> Population: 2,049,770
> Total area (including water) in square miles: 897.5 — 976 highest
> Land area square miles: 863.4 — 955 highest
> Population density: 2,445 — 51 highest

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14. San Bernardino, California
> Population: 2,149,031
> Total area (including water) in square miles: 20,105.3 — 12 highest
> Land area square miles: 20,052.5 — 10 highest
> Population density: 109 — 836 highest

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13. Clark, Nevada
> Population: 2,182,004
> Total area (including water) in square miles: 8,090.7 — 41 highest
> Land area square miles: 7,910.3 — 34 highest
> Population density: 286 — 431 highest

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12. King, Washington
> Population: 2,195,502
> Total area (including water) in square miles: 2,306.5 — 262 highest
> Land area square miles: 2,126.0 — 258 highest
> Population density: 1,068 — 141 highest

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11. Queens, New York
> Population: 2,287,388
> Total area (including water) in square miles: 178.3 — 3,044 highest
> Land area square miles: 109.2 — 3,076 highest
> Population density: 22,020 — 4 highest

Source: MattGush / Getty Images

10. Riverside, California
> Population: 2,411,439
> Total area (including water) in square miles: 7,303.1 — 46 highest
> Land area square miles: 7,207.4 — 42 highest
> Population density: 336 — 383 highest

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9. Kings, New York
> Population: 2,589,974
> Total area (including water) in square miles: 96.9 — 3,092 highest
> Land area square miles: 70.6 — 3,090 highest
> Population density: 38,749 — 2 highest

Source: f11photo / iStock via Getty Images

8. Dallas, Texas
> Population: 2,606,868
> Total area (including water) in square miles: 908.6 — 922 highest
> Land area square miles: 879.6 — 913 highest
> Population density: 2,971 — 33 highest

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7. Miami-Dade, Florida
> Population: 2,699,428
> Total area (including water) in square miles: 2,431.3 — 236 highest
> Land area square miles: 1,946.1 — 288 highest
> Population density: 1,388 — 111 highest

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6. Orange, California
> Population: 3,168,044
> Total area (including water) in square miles: 948.0 — 839 highest
> Land area square miles: 789.4 — 1,092 highest
> Population density: 4,037 — 25 highest

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5. San Diego, California
> Population: 3,316,073
> Total area (including water) in square miles: 4,525.5 — 105 highest
> Land area square miles: 4,199.9 — 109 highest
> Population density: 785 — 186 highest

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4. Maricopa, Arizona
> Population: 4,328,810
> Total area (including water) in square miles: 9,224.3 — 33 highest
> Land area square miles: 9,203.1 — 26 highest
> Population density: 480 — 278 highest

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3. Harris, Texas
> Population: 4,646,630
> Total area (including water) in square miles: 1,777.7 — 373 highest
> Land area square miles: 1,728.8 — 341 highest
> Population density: 2,737 — 44 highest

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2. Cook, Illinois
> Population: 5,198,275
> Total area (including water) in square miles: 1,635.0 — 408 highest
> Land area square miles: 945.7 — 746 highest
> Population density: 5,579 — 16 highest

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1. Los Angeles, California
> Population: 10,081,570
> Total area (including water) in square miles: 4,752.3 — 95 highest
> Land area square miles: 4,060.9 — 116 highest
> Population density: 2,466 — 49 highest

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