List of the most populous counties in the United States
List of the most populous US counties sorted according to the mid-2011 official estimate by the USCB
Columns: Rank | County | State | Land area (km²) | Land area (mi²) | April 1, 2010 census | April 1, 2010 density (/km²) | April 1, 2010 density (/mi²) | July 1, 2010 official estimate | July 1, 2010 density (/km²) | July 1, 2010 density (/mi²) | July 1, 2011 official estimate | July 1, 2011 density (/km²) | July 1, 2011 density (/mi²) | Mid-2010 to mid-2011 change (Absolute) | Mid-2010 to mid-2011 change (%) | County seat or courthouse
1 | Los Angeles County | California | 10,509.87 | 4,057.88 | 9,818,605 | 934 | 2,420 | 9,826,773 | 935 | 2,422 | 9,889,056 | 941 | 2,437 | 62,283 | 0.63 | Los Angeles | 2 | Cook County | Illinois | 2,448.38 | 945.33 | 5,194,675 | 2,122 | 5,495 | 5,199,971 | 2,124 | 5,501 | 5,217,080 | 2,131 | 5,519 | 17,109 | 0.33 | Chicago | 3 | Harris County | Texas | 4,411.99 | 1,703.48 | 4,092,459 | 928 | 2,402 | 4,109,362 | 931 | 2,412 | 4,180,894 | 948 | 2,454 | 71,532 | 1.74 | Houston | 4 | Maricopa County | Arizona | 23,828.26 | 9,200.14 | 3,817,117 | 160 | 415 | 3,824,834 | 161 | 416 | 3,880,244 | 163 | 422 | 55,410 | 1.45 | Phoenix | 5 | San Diego County | California | 10,895.12 | 4,206.63 | 3,095,313 | 284 | 736 | 3,105,115 | 285 | 738 | 3,140,069 | 288 | 746 | 34,954 | 1.13 | San Diego | 6 | Orange County | California | 2,047.56 | 790.57 | 3,010,232 | 1,470 | 3,808 | 3,017,598 | 1,474 | 3,817 | 3,055,745 | 1,492 | 3,865 | 38,147 | 1.26 | Santa Ana | 7 | Miami-Dade County | Florida | 4,915.06 | 1,897.72 | 2,496,435 | 508 | 1,315 | 2,503,034 | 509 | 1,319 | 2,554,766 | 520 | 1,346 | 51,732 | 2.07 | Miami | 8 | Kings County | New York | 183.41 | 70.82 | 2,504,700 | 13,656 | 35,370 | 2,508,515 | 13,677 | 35,423 | 2,532,645 | 13,809 | 35,764 | 24,130 | 0.96 | Brooklyn | 9 | Dallas County | Texas | 2,256.60 | 871.28 | 2,368,139 | 1,049 | 2,718 | 2,375,207 | 1,053 | 2,726 | 2,416,014 | 1,071 | 2,773 | 40,807 | 1.72 | Dallas | 10 | Queens County | New York | 281.10 | 108.53 | 2,230,722 | 7,936 | 20,553 | 2,233,895 | 7,947 | 20,583 | 2,247,848 | 7,997 | 20,711 | 13,953 | 0.62 | Jamaica | 11 | Riverside County | California | 18,664.70 | 7,206.48 | 2,189,641 | 117 | 304 | 2,202,978 | 118 | 306 | 2,239,620 | 120 | 311 | 36,642 | 1.66 | Riverside | 12 | San Bernardino County | California | 51,947.23 | 20,056.94 | 2,035,210 | 39 | 101 | 2,042,027 | 39 | 102 | 2,065,377 | 40 | 103 | 23,350 | 1.14 | San Bernardino | 13 | Clark County | Nevada | 20,438.71 | 7,891.43 | 1,951,269 | 95 | 247 | 1,953,927 | 96 | 248 | 1,969,975 | 96 | 250 | 16,048 | 0.82 | Las Vegas | 14 | King County | Washington | 5,479.29 | 2,115.57 | 1,931,249 | 352 | 913 | 1,937,157 | 354 | 916 | 1,969,722 | 359 | 931 | 32,565 | 1.68 | Seattle | 15 | Tarrant County | Texas | 2,236.74 | 863.61 | 1,809,034 | 809 | 2,095 | 1,816,850 | 812 | 2,104 | 1,849,815 | 827 | 2,142 | 32,965 | 1.81 | Fort Worth | 16 | Santa Clara County | California | 3,341.34 | 1,290.10 | 1,781,642 | 533 | 1,381 | 1,786,267 | 535 | 1,385 | 1,809,378 | 542 | 1,403 | 23,111 | 1.29 | San Jose | 17 | Wayne County | Michigan | 1,585.28 | 612.08 | 1,820,584 | 1,148 | 2,974 | 1,815,246 | 1,145 | 2,966 | 1,802,096 | 1,137 | 2,944 | -13,150 | -0.72 | Detroit | 18 | Broward County | Florida | 3,133.33 | 1,209.79 | 1,748,066 | 558 | 1,445 | 1,752,122 | 559 | 1,448 | 1,780,172 | 568 | 1,471 | 28,050 | 1.60 | Fort Lauderdale | 19 | Bexar County | Texas | 3,211.12 | 1,239.82 | 1,714,773 | 534 | 1,383 | 1,723,561 | 537 | 1,390 | 1,756,153 | 547 | 1,416 | 32,592 | 1.89 | San Antonio | 20 | New York County | New York | 59.13 | 22.83 | 1,585,873 | 26,820 | 69,464 | 1,587,481 | 26,847 | 69,534 | 1,601,948 | 27,092 | 70,168 | 14,467 | 0.91 | New York | 21 | Philadelphia County | Pennsylvania | 347.32 | 134.10 | 1,526,006 | 4,394 | 11,380 | 1,528,074 | 4,400 | 11,395 | 1,536,471 | 4,424 | 11,458 | 8,397 | 0.55 | Philadelphia | 22 | Alameda County | California | 1,914.05 | 739.02 | 1,510,271 | 789 | 2,044 | 1,513,043 | 790 | 2,047 | 1,529,875 | 799 | 2,070 | 16,832 | 1.11 | Oakland | 23 | Middlesex County | Massachusetts | 2,118.14 | 817.82 | 1,503,085 | 710 | 1,838 | 1,505,720 | 711 | 1,841 | 1,518,171 | 717 | 1,856 | 12,451 | 0.83 | Cambridge | 24 | Suffolk County | New York | 2,362.20 | 912.05 | 1,493,350 | 632 | 1,637 | 1,494,388 | 633 | 1,638 | 1,498,816 | 635 | 1,643 | 4,428 | 0.30 | Riverhead | 25 | Sacramento County | California | 2,498.42 | 964.64 | 1,418,788 | 568 | 1,471 | 1,422,094 | 569 | 1,474 | 1,436,105 | 575 | 1,489 | 14,011 | 0.99 | Sacramento | 26 | Bronx County | New York | 109.03 | 42.10 | 1,385,108 | 12,704 | 32,903 | 1,387,159 | 12,723 | 32,952 | 1,392,002 | 12,767 | 33,067 | 4,843 | 0.35 | Bronx | 27 | Nassau County | New York | 737.41 | 284.72 | 1,339,532 | 1,817 | 4,705 | 1,341,033 | 1,819 | 4,710 | 1,344,436 | 1,823 | 4,722 | 3,403 | 0.25 | Mineola | 28 | Palm Beach County | Florida | 5,101.66 | 1,969.76 | 1,320,134 | 259 | 670 | 1,322,924 | 259 | 672 | 1,335,187 | 262 | 678 | 12,263 | 0.93 | West Palm Beach | 29 | Cuyahoga County | Ohio | 1,184.12 | 457.19 | 1,280,122 | 1,081 | 2,800 | 1,278,000 | 1,079 | 2,795 | 1,270,294 | 1,073 | 2,778 | -7,706 | -0.60 | Cleveland | 30 | Hillsborough County | Florida | 2,642.34 | 1,020.21 | 1,229,226 | 465 | 1,205 | 1,233,373 | 467 | 1,209 | 1,267,775 | 480 | 1,243 | 34,402 | 2.79 | Tampa | 31 | Allegheny County | Pennsylvania | 1,890.88 | 730.07 | 1,223,348 | 647 | 1,676 | 1,224,833 | 648 | 1,678 | 1,227,066 | 649 | 1,681 | 2,233 | 0.18 | Pittsburgh | 32 | Oakland County | Michigan | 2,247.24 | 867.66 | 1,202,362 | 535 | 1,386 | 1,202,682 | 535 | 1,386 | 1,210,145 | 539 | 1,395 | 7,463 | 0.62 | Pontiac | 33 | Franklin County | Ohio | 1,378.36 | 532.19 | 1,163,414 | 844 | 2,186 | 1,165,789 | 846 | 2,191 | 1,178,799 | 855 | 2,215 | 13,010 | 1.12 | Columbus | 34 | Orange County | Florida | 2,339.87 | 903.43 | 1,145,956 | 490 | 1,268 | 1,148,787 | 491 | 1,272 | 1,169,107 | 500 | 1,294 | 20,320 | 1.77 | Orlando | 35 | Hennepin County | Minnesota | 1,433.79 | 553.59 | 1,152,425 | 804 | 2,082 | 1,154,067 | 805 | 2,085 | 1,168,431 | 815 | 2,111 | 14,364 | 1.24 | Minneapolis | 36 | Fairfax County | Virginia | 1,012.60 | 390.97 | 1,081,726 | 1,068 | 2,767 | 1,085,934 | 1,072 | 2,778 | 1,100,692 | 1,087 | 2,815 | 14,758 | 1.36 | Fairfax | 37 | Contra Costa County | California | 1,854.27 | 715.94 | 1,049,025 | 566 | 1,465 | 1,052,605 | 568 | 1,470 | 1,066,096 | 575 | 1,489 | 13,491 | 1.28 | Martinez | 38 | Travis County | Texas | 2,564.61 | 990.20 | 1,024,266 | 399 | 1,034 | 1,030,588 | 402 | 1,041 | 1,063,130 | 415 | 1,074 | 32,542 | 3.16 | Austin | 39 | Salt Lake County | Utah | 1,922.50 | 742.28 | 1,029,655 | 536 | 1,387 | 1,033,223 | 537 | 1,392 | 1,048,985 | 546 | 1,413 | 15,762 | 1.53 | Salt Lake City | 40 | St. Louis County | Missouri | 1,315.20 | 507.80 | 998,954 | 760 | 1,967 | 998,772 | 759 | 1,967 | 998,692 | 759 | 1,967 | -80 | -0.01 | Clayton | 41 | Montgomery County | Maryland | 1,272.34 | 491.25 | 971,777 | 764 | 1,978 | 975,439 | 767 | 1,986 | 989,794 | 778 | 2,015 | 14,355 | 1.47 | Rockville | 42 | Pima County | Arizona | 23,794.31 | 9,187.04 | 980,263 | 41 | 107 | 982,108 | 41 | 107 | 989,569 | 42 | 108 | 7,461 | 0.76 | Tucson | 43 | Honolulu County | Hawaii | 1,555.92 | 600.74 | 953,207 | 613 | 1,587 | 955,636 | 614 | 1,591 | 963,607 | 619 | 1,604 | 7,971 | 0.83 | Honolulu | 44 | Westchester County | New York | 1,114.98 | 430.50 | 949,113 | 851 | 2,205 | 950,283 | 852 | 2,207 | 955,899 | 857 | 2,220 | 5,616 | 0.59 | White Plains | 45 | Milwaukee County | Wisconsin | 625.23 | 241.40 | 947,735 | 1,516 | 3,926 | 948,623 | 1,517 | 3,930 | 952,532 | 1,523 | 3,946 | 3,909 | 0.41 | Milwaukee | 46 | Fulton County | Georgia | 1,363.98 | 526.63 | 920,581 | 675 | 1,748 | 925,920 | 679 | 1,758 | 949,599 | 696 | 1,803 | 23,679 | 2.56 | Atlanta | 47 | Mecklenburg County | North Carolina | 1,356.75 | 523.84 | 919,628 | 678 | 1,756 | 923,141 | 680 | 1,762 | 944,373 | 696 | 1,803 | 21,232 | 2.30 | Charlotte | 48 | Fresno County | California | 15,431.13 | 5,957.99 | 930,450 | 60 | 156 | 933,168 | 60 | 157 | 942,904 | 61 | 158 | 9,736 | 1.04 | Fresno | 49 | Shelby County | Tennessee | 1,976.61 | 763.17 | 927,644 | 469 | 1,216 | 928,930 | 470 | 1,217 | 935,088 | 473 | 1,225 | 6,158 | 0.66 | Memphis | 50 | Wake County | North Carolina | 2,163.21 | 835.22 | 900,993 | 417 | 1,079 | 906,788 | 419 | 1,086 | 929,780 | 430 | 1,113 | 22,992 | 2.54 | Raleigh | 51 | Fairfield County | Connecticut | 1,618.46 | 624.89 | 916,829 | 566 | 1,467 | 918,339 | 567 | 1,470 | 925,899 | 572 | 1,482 | 7,560 | 0.82 | Bridgeport | 52 | DuPage County | Illinois | 848.22 | 327.50 | 916,924 | 1,081 | 2,800 | 917,942 | 1,082 | 2,803 | 923,222 | 1,088 | 2,819 | 5,280 | 0.58 | Wheaton | 53 | Erie County | New York | 2,700.56 | 1,042.69 | 919,040 | 340 | 881 | 918,751 | 340 | 881 | 918,028 | 340 | 880 | -,723 | -0.08 | Buffalo | 54 | Pinellas County | Florida | 709.14 | 273.80 | 916,542 | 1,292 | 3,347 | 916,220 | 1,292 | 3,346 | 917,398 | 1,294 | 3,351 | 1,178 | 0.13 | Clearwater | 55 | Marion County | Indiana | 1,026.41 | 396.30 | 903,393 | 880 | 2,280 | 904,789 | 882 | 2,283 | 911,296 | 888 | 2,300 | 6,507 | 0.72 | Indianapolis | 56 | Bergen County | New Jersey | 603.49 | 233.01 | 905,116 | 1,500 | 3,884 | 906,184 | 1,502 | 3,889 | 911,004 | 1,510 | 3,910 | 4,820 | 0.53 | Hackensack | 57 | Hartford County | Connecticut | 1,903.89 | 735.10 | 894,014 | 470 | 1,216 | 894,127 | 470 | 1,216 | 894,705 | 470 | 1,217 | 578 | 0.06 | Hartford | 58 | Prince George's County | Maryland | 1,250.16 | 482.69 | 863,420 | 691 | 1,789 | 865,219 | 692 | 1,792 | 871,233 | 697 | 1,805 | 6,014 | 0.70 | Upper Marlboro | 59 | Duval County | Florida | 1,974.07 | 762.19 | 864,263 | 438 | 1,134 | 865,420 | 438 | 1,135 | 870,709 | 441 | 1,142 | 5,289 | 0.61 | Jacksonville | 60 | New Haven County | Connecticut | 1,565.66 | 604.51 | 862,477 | 551 | 1,427 | 862,438 | 551 | 1,427 | 861,113 | 550 | 1,424 | -1,325 | -0.15 | New Haven and Waterbury | 61 | Kern County | California | 21,061.57 | 8,131.92 | 839,631 | 40 | 103 | 842,813 | 40 | 104 | 851,710 | 40 | 105 | 8,897 | 1.06 | Bakersfield | 62 | Macomb County | Michigan | 1,241.18 | 479.22 | 840,978 | 678 | 1,755 | 840,944 | 678 | 1,755 | 842,145 | 679 | 1,757 | 1,201 | 0.14 | Mount Clemens | 63 | Ventura County | California | 4,773.69 | 1,843.13 | 823,318 | 172 | 447 | 825,445 | 173 | 448 | 831,771 | 174 | 451 | 6,326 | 0.77 | Ventura | 64 | Gwinnett County | Georgia | 1,114.69 | 430.38 | 805,321 | 722 | 1,871 | 808,291 | 725 | 1,878 | 824,941 | 740 | 1,917 | 16,650 | 2.06 | Lawrenceville | 65 | El Paso County | Texas | 2,622.86 | 1,012.69 | 800,647 | 305 | 791 | 803,995 | 307 | 794 | 820,790 | 313 | 811 | 16,795 | 2.09 | El Paso | 66 | Middlesex County | New Jersey | 800.08 | 308.91 | 809,858 | 1,012 | 2,622 | 810,747 | 1,013 | 2,625 | 814,217 | 1,018 | 2,636 | 3,470 | 0.43 | New Brunswick | 67 | San Francisco County | California | 121.40 | 46.87 | 805,235 | 6,633 | 17,179 | 805,340 | 6,634 | 17,181 | 812,826 | 6,695 | 17,341 | 7,486 | 0.93 | San Francisco | 68 | Collin County | Texas | 2,178.76 | 841.22 | 782,341 | 359 | 930 | 788,511 | 362 | 937 | 812,226 | 373 | 966 | 23,715 | 3.01 | McKinney | 69 | Baltimore County | Maryland | 1,549.59 | 598.30 | 805,029 | 520 | 1,346 | 805,964 | 520 | 1,347 | 809,941 | 523 | 1,354 | 3,977 | 0.49 | Towson | 70 | Pierce County | Washington | 4,324.01 | 1,669.51 | 795,225 | 184 | 476 | 795,371 | 184 | 476 | 807,904 | 187 | 484 | 12,533 | 1.58 | Tacoma | 71 | Montgomery County | Pennsylvania | 1,251.07 | 483.04 | 799,874 | 639 | 1,656 | 800,482 | 640 | 1,657 | 804,210 | 643 | 1,665 | 3,728 | 0.47 | Norristown | 72 | Worcester County | Massachusetts | 3,912.88 | 1,510.77 | 798,552 | 204 | 529 | 799,300 | 204 | 529 | 801,227 | 205 | 530 | 1,927 | 0.24 | Worcester | 73 | Hamilton County | Ohio | 1,051.30 | 405.91 | 802,374 | 763 | 1,977 | 801,948 | 763 | 1,976 | 800,362 | 761 | 1,972 | -1,586 | -0.20 | Cincinnati | 74 | Hidalgo County | Texas | 4,068.52 | 1,570.87 | 774,769 | 190 | 493 | 780,030 | 192 | 497 | 797,810 | 196 | 508 | 17,780 | 2.28 | Edinburg | 75 | Essex County | New Jersey | 326.89 | 126.21 | 783,969 | 2,398 | 6,211 | 784,099 | 2,399 | 6,213 | 785,137 | 2,402 | 6,221 | 1,038 | 0.13 | Newark | 76 | Essex County | Massachusetts | 1,275.73 | 492.56 | 743,159 | 583 | 1,509 | 744,484 | 584 | 1,511 | 748,930 | 587 | 1,520 | 4,446 | 0.60 | Salem | 77 | Multnomah County | Oregon | 1,117.05 | 431.30 | 735,334 | 658 | 1,705 | 737,476 | 660 | 1,710 | 748,031 | 670 | 1,734 | 10,555 | 1.43 | Portland | 78 | Jefferson County | Kentucky | 985.27 | 380.42 | 741,096 | 752 | 1,948 | 742,176 | 753 | 1,951 | 746,906 | 758 | 1,963 | 4,730 | 0.64 | Louisville | 79 | Monroe County | New York | 1,702.15 | 657.21 | 744,344 | 437 | 1,133 | 744,635 | 437 | 1,133 | 745,625 | 438 | 1,135 | 990 | 0.13 | Rochester | 80 | Oklahoma County | Oklahoma | 1,835.83 | 708.82 | 718,633 | 391 | 1,014 | 721,298 | 393 | 1,018 | 732,371 | 399 | 1,033 | 11,073 | 1.54 | Oklahoma City | 81 | Suffolk County | Massachusetts | 150.62 | 58.15 | 722,023 | 4,794 | 12,416 | 722,731 | 4,798 | 12,428 | 730,932 | 4,853 | 12,569 | 8,201 | 1.13 | Boston | 82 | San Mateo County | California | 1,161.37 | 448.41 | 718,451 | 619 | 1,602 | 719,604 | 620 | 1,605 | 727,209 | 626 | 1,622 | 7,605 | 1.06 | Redwood City | 83 | Snohomish County | Washington | 5,406.01 | 2,087.27 | 713,335 | 132 | 342 | 715,358 | 132 | 343 | 722,400 | 134 | 346 | 7,042 | 0.98 | Everett | 84 | Lake County | Illinois | 1,149.10 | 443.67 | 703,462 | 612 | 1,586 | 704,492 | 613 | 1,588 | 706,222 | 615 | 1,592 | 1,730 | 0.25 | Waukegan | 85 | DeKalb County | Georgia | 693.03 | 267.58 | 691,893 | 998 | 2,586 | 692,858 | 1,000 | 2,589 | 699,893 | 1,010 | 2,616 | 7,035 | 1.02 | Decatur | 86 | Cobb County | Georgia | 879.43 | 339.55 | 688,078 | 782 | 2,026 | 689,749 | 784 | 2,031 | 697,553 | 793 | 2,054 | 7,804 | 1.13 | Marietta | 87 | San Joaquin County | California | 3,603.51 | 1,391.32 | 685,306 | 190 | 493 | 687,661 | 191 | 494 | 696,214 | 193 | 500 | 8,553 | 1.24 | Stockton | 88 | Denton County | Texas | 2,275.13 | 878.43 | 662,614 | 291 | 754 | 667,138 | 293 | 759 | 686,406 | 302 | 781 | 19,268 | 2.89 | Denton | 89 | Will County | Illinois | 2,167.58 | 836.91 | 677,560 | 313 | 810 | 678,873 | 313 | 811 | 681,545 | 314 | 814 | 2,672 | 0.39 | Joliet | 90 | Jackson County | Missouri | 1,565.55 | 604.46 | 674,158 | 431 | 1,115 | 674,953 | 431 | 1,117 | 676,360 | 432 | 1,119 | 1,407 | 0.21 | Independence, Missouri and Kansas City | 91 | Norfolk County | Massachusetts | 1,025.91 | 396.11 | 670,850 | 654 | 1,694 | 672,107 | 655 | 1,697 | 675,436 | 658 | 1,705 | 3,329 | 0.50 | Dedham | 92 | Bernalillo County | New Mexico | 3,006.53 | 1,160.83 | 662,564 | 220 | 571 | 664,425 | 221 | 572 | 670,968 | 223 | 578 | 6,543 | 0.98 | Albuquerque | 93 | Jefferson County | Alabama | 2,878.19 | 1,111.28 | 658,466 | 229 | 593 | 658,386 | 229 | 592 | 658,931 | 229 | 593 | 545 | 0.08 | Birmingham | 94 | Hudson County | New Jersey | 119.63 | 46.19 | 634,266 | 5,302 | 13,732 | 634,979 | 5,308 | 13,747 | 641,224 | 5,360 | 13,882 | 6,245 | 0.98 | Jersey City | 95 | El Paso County | Colorado | 5,508.39 | 2,126.80 | 622,263 | 113 | 293 | 627,159 | 114 | 295 | 636,963 | 116 | 299 | 9,804 | 1.56 | Colorado Springs | 96 | Davidson County | Tennessee | 1,305.44 | 504.03 | 626,681 | 480 | 1,243 | 628,053 | 481 | 1,246 | 635,475 | 487 | 1,261 | 7,422 | 1.18 | Nashville | 97 | Lee County | Florida | 2,031.88 | 784.51 | 618,754 | 305 | 789 | 620,450 | 305 | 791 | 631,330 | 311 | 805 | 10,880 | 1.75 | Fort Myers | 98 | Monmouth County | New Jersey | 1,214.17 | 468.79 | 630,380 | 519 | 1,345 | 630,920 | 520 | 1,346 | 631,020 | 520 | 1,346 | 100 | 0.02 | Freehold | 99 | Bucks County | Pennsylvania | 1,565.15 | 604.31 | 625,249 | 399 | 1,035 | 625,618 | 400 | 1,035 | 626,854 | 401 | 1,037 | 1,236 | 0.20 | Doylestown | 100 | Providence County | Rhode Island | 1,060.60 | 409.50 | 626,667 | 591 | 1,530 | 626,797 | 591 | 1,531 | 626,709 | 591 | 1,530 | -88 | -0.01 | Providence | Rank | County | State | Land area (km²) | Land area (mi²) | April 1, 2010 census | April 1, 2010 density (/km²) | April 1, 2010 density (/mi²) | July 1, 2010 official estimate | July 1, 2010 density (/km²) | July 1, 2010 density (/mi²) | July 1, 2011 official estimate | July 1, 2011 density (/km²) | July 1, 2011 density (/mi²) | Mid-2010 to mid-2011 change (Absolute) | Mid-2010 to mid-2011 change (%) | County seat or courthouse