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 | 9818605 | 934 | 2420 | 9826773 | 935 | 2422 | 9889056 | 941 | 2437 | 62283 | 0.63 | Los Angeles | 2 | Cook County | Illinois | 2,448.38 | 945.33 | 5194675 | 2122 | 5495 | 5199971 | 2124 | 5501 | 5217080 | 2131 | 5519 | 17109 | 0.33 | Chicago | 3 | Harris County | Texas | 4,411.99 | 1,703.48 | 4092459 | 928 | 2402 | 4109362 | 931 | 2412 | 4180894 | 948 | 2454 | 71532 | 1.74 | Houston | 4 | Maricopa County | Arizona | 23,828.26 | 9,200.14 | 3817117 | 160 | 415 | 3824834 | 161 | 416 | 3880244 | 163 | 422 | 55410 | 1.45 | Phoenix | 5 | San Diego County | California | 10,895.12 | 4,206.63 | 3095313 | 284 | 736 | 3105115 | 285 | 738 | 3140069 | 288 | 746 | 34954 | 1.13 | San Diego | 6 | Orange County | California | 2,047.56 | 790.57 | 3010232 | 1470 | 3808 | 3017598 | 1474 | 3817 | 3055745 | 1492 | 3865 | 38147 | 1.26 | Santa Ana | 7 | Miami-Dade County | Florida | 4,915.06 | 1,897.72 | 2496435 | 508 | 1315 | 2503034 | 509 | 1319 | 2554766 | 520 | 1346 | 51732 | 2.07 | Miami | 8 | Kings County | New York | 183.41 | 70.82 | 2504700 | 13656 | 35370 | 2508515 | 13677 | 35423 | 2532645 | 13809 | 35764 | 24130 | 0.96 | Brooklyn | 9 | Dallas County | Texas | 2,256.60 | 871.28 | 2368139 | 1049 | 2718 | 2375207 | 1053 | 2726 | 2416014 | 1071 | 2773 | 40807 | 1.72 | Dallas | 10 | Queens County | New York | 281.10 | 108.53 | 2230722 | 7936 | 20553 | 2233895 | 7947 | 20583 | 2247848 | 7997 | 20711 | 13953 | 0.62 | Jamaica | 11 | Riverside County | California | 18,664.70 | 7,206.48 | 2189641 | 117 | 304 | 2202978 | 118 | 306 | 2239620 | 120 | 311 | 36642 | 1.66 | Riverside | 12 | San Bernardino County | California | 51,947.23 | 20,056.94 | 2035210 | 39 | 101 | 2042027 | 39 | 102 | 2065377 | 40 | 103 | 23350 | 1.14 | San Bernardino | 13 | Clark County | Nevada | 20,438.71 | 7,891.43 | 1951269 | 95 | 247 | 1953927 | 96 | 248 | 1969975 | 96 | 250 | 16048 | 0.82 | Las Vegas | 14 | King County | Washington | 5,479.29 | 2,115.57 | 1931249 | 352 | 913 | 1937157 | 354 | 916 | 1969722 | 359 | 931 | 32565 | 1.68 | Seattle | 15 | Tarrant County | Texas | 2,236.74 | 863.61 | 1809034 | 809 | 2095 | 1816850 | 812 | 2104 | 1849815 | 827 | 2142 | 32965 | 1.81 | Fort Worth | 16 | Santa Clara County | California | 3,341.34 | 1,290.10 | 1781642 | 533 | 1381 | 1786267 | 535 | 1385 | 1809378 | 542 | 1403 | 23111 | 1.29 | San Jose | 17 | Wayne County | Michigan | 1,585.28 | 612.08 | 1820584 | 1148 | 2974 | 1815246 | 1145 | 2966 | 1802096 | 1137 | 2944 | -13150 | -0.72 | Detroit | 18 | Broward County | Florida | 3,133.33 | 1,209.79 | 1748066 | 558 | 1445 | 1752122 | 559 | 1448 | 1780172 | 568 | 1471 | 28050 | 1.60 | Fort Lauderdale | 19 | Bexar County | Texas | 3,211.12 | 1,239.82 | 1714773 | 534 | 1383 | 1723561 | 537 | 1390 | 1756153 | 547 | 1416 | 32592 | 1.89 | San Antonio | 20 | New York County | New York | 59.13 | 22.83 | 1585873 | 26820 | 69464 | 1587481 | 26847 | 69534 | 1601948 | 27092 | 70168 | 14467 | 0.91 | New York | 21 | Philadelphia County | Pennsylvania | 347.32 | 134.10 | 1526006 | 4394 | 11380 | 1528074 | 4400 | 11395 | 1536471 | 4424 | 11458 | 8397 | 0.55 | Philadelphia | 22 | Alameda County | California | 1,914.05 | 739.02 | 1510271 | 789 | 2044 | 1513043 | 790 | 2047 | 1529875 | 799 | 2070 | 16832 | 1.11 | Oakland | 23 | Middlesex County | Massachusetts | 2,118.14 | 817.82 | 1503085 | 710 | 1838 | 1505720 | 711 | 1841 | 1518171 | 717 | 1856 | 12451 | 0.83 | Cambridge | 24 | Suffolk County | New York | 2,362.20 | 912.05 | 1493350 | 632 | 1637 | 1494388 | 633 | 1638 | 1498816 | 635 | 1643 | 4428 | 0.30 | Riverhead | 25 | Sacramento County | California | 2,498.42 | 964.64 | 1418788 | 568 | 1471 | 1422094 | 569 | 1474 | 1436105 | 575 | 1489 | 14011 | 0.99 | Sacramento | 26 | Bronx County | New York | 109.03 | 42.10 | 1385108 | 12704 | 32903 | 1387159 | 12723 | 32952 | 1392002 | 12767 | 33067 | 4843 | 0.35 | Bronx | 27 | Nassau County | New York | 737.41 | 284.72 | 1339532 | 1817 | 4705 | 1341033 | 1819 | 4710 | 1344436 | 1823 | 4722 | 3403 | 0.25 | Mineola | 28 | Palm Beach County | Florida | 5,101.66 | 1,969.76 | 1320134 | 259 | 670 | 1322924 | 259 | 672 | 1335187 | 262 | 678 | 12263 | 0.93 | West Palm Beach | 29 | Cuyahoga County | Ohio | 1,184.12 | 457.19 | 1280122 | 1081 | 2800 | 1278000 | 1079 | 2795 | 1270294 | 1073 | 2778 | -7706 | -0.60 | Cleveland | 30 | Hillsborough County | Florida | 2,642.34 | 1,020.21 | 1229226 | 465 | 1205 | 1233373 | 467 | 1209 | 1267775 | 480 | 1243 | 34402 | 2.79 | Tampa | 31 | Allegheny County | Pennsylvania | 1,890.88 | 730.07 | 1223348 | 647 | 1676 | 1224833 | 648 | 1678 | 1227066 | 649 | 1681 | 2233 | 0.18 | Pittsburgh | 32 | Oakland County | Michigan | 2,247.24 | 867.66 | 1202362 | 535 | 1386 | 1202682 | 535 | 1386 | 1210145 | 539 | 1395 | 7463 | 0.62 | Pontiac | 33 | Franklin County | Ohio | 1,378.36 | 532.19 | 1163414 | 844 | 2186 | 1165789 | 846 | 2191 | 1178799 | 855 | 2215 | 13010 | 1.12 | Columbus | 34 | Orange County | Florida | 2,339.87 | 903.43 | 1145956 | 490 | 1268 | 1148787 | 491 | 1272 | 1169107 | 500 | 1294 | 20320 | 1.77 | Orlando | 35 | Hennepin County | Minnesota | 1,433.79 | 553.59 | 1152425 | 804 | 2082 | 1154067 | 805 | 2085 | 1168431 | 815 | 2111 | 14364 | 1.24 | Minneapolis | 36 | Fairfax County | Virginia | 1,012.60 | 390.97 | 1081726 | 1068 | 2767 | 1085934 | 1072 | 2778 | 1100692 | 1087 | 2815 | 14758 | 1.36 | Fairfax | 37 | Contra Costa County | California | 1,854.27 | 715.94 | 1049025 | 566 | 1465 | 1052605 | 568 | 1470 | 1066096 | 575 | 1489 | 13491 | 1.28 | Martinez | 38 | Travis County | Texas | 2,564.61 | 990.20 | 1024266 | 399 | 1034 | 1030588 | 402 | 1041 | 1063130 | 415 | 1074 | 32542 | 3.16 | Austin | 39 | Salt Lake County | Utah | 1,922.50 | 742.28 | 1029655 | 536 | 1387 | 1033223 | 537 | 1392 | 1048985 | 546 | 1413 | 15762 | 1.53 | Salt Lake City | 40 | St. Louis County | Missouri | 1,315.20 | 507.80 | 998954 | 760 | 1967 | 998772 | 759 | 1967 | 998692 | 759 | 1967 | -80 | -0.01 | Clayton | 41 | Montgomery County | Maryland | 1,272.34 | 491.25 | 971777 | 764 | 1978 | 975439 | 767 | 1986 | 989794 | 778 | 2015 | 14355 | 1.47 | Rockville | 42 | Pima County | Arizona | 23,794.31 | 9,187.04 | 980263 | 41 | 107 | 982108 | 41 | 107 | 989569 | 42 | 108 | 7461 | 0.76 | Tucson | 43 | Honolulu County | Hawaii | 1,555.92 | 600.74 | 953207 | 613 | 1587 | 955636 | 614 | 1591 | 963607 | 619 | 1604 | 7971 | 0.83 | Honolulu | 44 | Westchester County | New York | 1,114.98 | 430.50 | 949113 | 851 | 2205 | 950283 | 852 | 2207 | 955899 | 857 | 2220 | 5616 | 0.59 | White Plains | 45 | Milwaukee County | Wisconsin | 625.23 | 241.40 | 947735 | 1516 | 3926 | 948623 | 1517 | 3930 | 952532 | 1523 | 3946 | 3909 | 0.41 | Milwaukee | 46 | Fulton County | Georgia | 1,363.98 | 526.63 | 920581 | 675 | 1748 | 925920 | 679 | 1758 | 949599 | 696 | 1803 | 23679 | 2.56 | Atlanta | 47 | Mecklenburg County | North Carolina | 1,356.75 | 523.84 | 919628 | 678 | 1756 | 923141 | 680 | 1762 | 944373 | 696 | 1803 | 21232 | 2.30 | Charlotte | 48 | Fresno County | California | 15,431.13 | 5,957.99 | 930450 | 60 | 156 | 933168 | 60 | 157 | 942904 | 61 | 158 | 9736 | 1.04 | Fresno | 49 | Shelby County | Tennessee | 1,976.61 | 763.17 | 927644 | 469 | 1216 | 928930 | 470 | 1217 | 935088 | 473 | 1225 | 6158 | 0.66 | Memphis | 50 | Wake County | North Carolina | 2,163.21 | 835.22 | 900993 | 417 | 1079 | 906788 | 419 | 1086 | 929780 | 430 | 1113 | 22992 | 2.54 | Raleigh | 51 | Fairfield County | Connecticut | 1,618.46 | 624.89 | 916829 | 566 | 1467 | 918339 | 567 | 1470 | 925899 | 572 | 1482 | 7560 | 0.82 | Bridgeport | 52 | DuPage County | Illinois | 848.22 | 327.50 | 916924 | 1081 | 2800 | 917942 | 1082 | 2803 | 923222 | 1088 | 2819 | 5280 | 0.58 | Wheaton | 53 | Erie County | New York | 2,700.56 | 1,042.69 | 919040 | 340 | 881 | 918751 | 340 | 881 | 918028 | 340 | 880 | -723 | -0.08 | Buffalo | 54 | Pinellas County | Florida | 709.14 | 273.80 | 916542 | 1292 | 3347 | 916220 | 1292 | 3346 | 917398 | 1294 | 3351 | 1178 | 0.13 | Clearwater | 55 | Marion County | Indiana | 1,026.41 | 396.30 | 903393 | 880 | 2280 | 904789 | 882 | 2283 | 911296 | 888 | 2300 | 6507 | 0.72 | Indianapolis | 56 | Bergen County | New Jersey | 603.49 | 233.01 | 905116 | 1500 | 3884 | 906184 | 1502 | 3889 | 911004 | 1510 | 3910 | 4820 | 0.53 | Hackensack | 57 | Hartford County | Connecticut | 1,903.89 | 735.10 | 894014 | 470 | 1216 | 894127 | 470 | 1216 | 894705 | 470 | 1217 | 578 | 0.06 | Hartford | 58 | Prince George's County | Maryland | 1,250.16 | 482.69 | 863420 | 691 | 1789 | 865219 | 692 | 1792 | 871233 | 697 | 1805 | 6014 | 0.70 | Upper Marlboro | 59 | Duval County | Florida | 1,974.07 | 762.19 | 864263 | 438 | 1134 | 865420 | 438 | 1135 | 870709 | 441 | 1142 | 5289 | 0.61 | Jacksonville | 60 | New Haven County | Connecticut | 1,565.66 | 604.51 | 862477 | 551 | 1427 | 862438 | 551 | 1427 | 861113 | 550 | 1424 | -1325 | -0.15 | New Haven and Waterbury | 61 | Kern County | California | 21,061.57 | 8,131.92 | 839631 | 40 | 103 | 842813 | 40 | 104 | 851710 | 40 | 105 | 8897 | 1.06 | Bakersfield | 62 | Macomb County | Michigan | 1,241.18 | 479.22 | 840978 | 678 | 1755 | 840944 | 678 | 1755 | 842145 | 679 | 1757 | 1201 | 0.14 | Mount Clemens | 63 | Ventura County | California | 4,773.69 | 1,843.13 | 823318 | 172 | 447 | 825445 | 173 | 448 | 831771 | 174 | 451 | 6326 | 0.77 | Ventura | 64 | Gwinnett County | Georgia | 1,114.69 | 430.38 | 805321 | 722 | 1871 | 808291 | 725 | 1878 | 824941 | 740 | 1917 | 16650 | 2.06 | Lawrenceville | 65 | El Paso County | Texas | 2,622.86 | 1,012.69 | 800647 | 305 | 791 | 803995 | 307 | 794 | 820790 | 313 | 811 | 16795 | 2.09 | El Paso | 66 | Middlesex County | New Jersey | 800.08 | 308.91 | 809858 | 1012 | 2622 | 810747 | 1013 | 2625 | 814217 | 1018 | 2636 | 3470 | 0.43 | New Brunswick | 67 | San Francisco County | California | 121.40 | 46.87 | 805235 | 6633 | 17179 | 805340 | 6634 | 17181 | 812826 | 6695 | 17341 | 7486 | 0.93 | San Francisco | 68 | Collin County | Texas | 2,178.76 | 841.22 | 782341 | 359 | 930 | 788511 | 362 | 937 | 812226 | 373 | 966 | 23715 | 3.01 | McKinney | 69 | Baltimore County | Maryland | 1,549.59 | 598.30 | 805029 | 520 | 1346 | 805964 | 520 | 1347 | 809941 | 523 | 1354 | 3977 | 0.49 | Towson | 70 | Pierce County | Washington | 4,324.01 | 1,669.51 | 795225 | 184 | 476 | 795371 | 184 | 476 | 807904 | 187 | 484 | 12533 | 1.58 | Tacoma | 71 | Montgomery County | Pennsylvania | 1,251.07 | 483.04 | 799874 | 639 | 1656 | 800482 | 640 | 1657 | 804210 | 643 | 1665 | 3728 | 0.47 | Norristown | 72 | Worcester County | Massachusetts | 3,912.88 | 1,510.77 | 798552 | 204 | 529 | 799300 | 204 | 529 | 801227 | 205 | 530 | 1927 | 0.24 | Worcester | 73 | Hamilton County | Ohio | 1,051.30 | 405.91 | 802374 | 763 | 1977 | 801948 | 763 | 1976 | 800362 | 761 | 1972 | -1586 | -0.20 | Cincinnati | 74 | Hidalgo County | Texas | 4,068.52 | 1,570.87 | 774769 | 190 | 493 | 780030 | 192 | 497 | 797810 | 196 | 508 | 17780 | 2.28 | Edinburg | 75 | Essex County | New Jersey | 326.89 | 126.21 | 783969 | 2398 | 6211 | 784099 | 2399 | 6213 | 785137 | 2402 | 6221 | 1038 | 0.13 | Newark | 76 | Essex County | Massachusetts | 1,275.73 | 492.56 | 743159 | 583 | 1509 | 744484 | 584 | 1511 | 748930 | 587 | 1520 | 4446 | 0.60 | Salem | 77 | Multnomah County | Oregon | 1,117.05 | 431.30 | 735334 | 658 | 1705 | 737476 | 660 | 1710 | 748031 | 670 | 1734 | 10555 | 1.43 | Portland | 78 | Jefferson County | Kentucky | 985.27 | 380.42 | 741096 | 752 | 1948 | 742176 | 753 | 1951 | 746906 | 758 | 1963 | 4730 | 0.64 | Louisville | 79 | Monroe County | New York | 1,702.15 | 657.21 | 744344 | 437 | 1133 | 744635 | 437 | 1133 | 745625 | 438 | 1135 | 990 | 0.13 | Rochester | 80 | Oklahoma County | Oklahoma | 1,835.83 | 708.82 | 718633 | 391 | 1014 | 721298 | 393 | 1018 | 732371 | 399 | 1033 | 11073 | 1.54 | Oklahoma City | 81 | Suffolk County | Massachusetts | 150.62 | 58.15 | 722023 | 4794 | 12416 | 722731 | 4798 | 12428 | 730932 | 4853 | 12569 | 8201 | 1.13 | Boston | 82 | San Mateo County | California | 1,161.37 | 448.41 | 718451 | 619 | 1602 | 719604 | 620 | 1605 | 727209 | 626 | 1622 | 7605 | 1.06 | Redwood City | 83 | Snohomish County | Washington | 5,406.01 | 2,087.27 | 713335 | 132 | 342 | 715358 | 132 | 343 | 722400 | 134 | 346 | 7042 | 0.98 | Everett | 84 | Lake County | Illinois | 1,149.10 | 443.67 | 703462 | 612 | 1586 | 704492 | 613 | 1588 | 706222 | 615 | 1592 | 1730 | 0.25 | Waukegan | 85 | DeKalb County | Georgia | 693.03 | 267.58 | 691893 | 998 | 2586 | 692858 | 1000 | 2589 | 699893 | 1010 | 2616 | 7035 | 1.02 | Decatur | 86 | Cobb County | Georgia | 879.43 | 339.55 | 688078 | 782 | 2026 | 689749 | 784 | 2031 | 697553 | 793 | 2054 | 7804 | 1.13 | Marietta | 87 | San Joaquin County | California | 3,603.51 | 1,391.32 | 685306 | 190 | 493 | 687661 | 191 | 494 | 696214 | 193 | 500 | 8553 | 1.24 | Stockton | 88 | Denton County | Texas | 2,275.13 | 878.43 | 662614 | 291 | 754 | 667138 | 293 | 759 | 686406 | 302 | 781 | 19268 | 2.89 | Denton | 89 | Will County | Illinois | 2,167.58 | 836.91 | 677560 | 313 | 810 | 678873 | 313 | 811 | 681545 | 314 | 814 | 2672 | 0.39 | Joliet | 90 | Jackson County | Missouri | 1,565.55 | 604.46 | 674158 | 431 | 1115 | 674953 | 431 | 1117 | 676360 | 432 | 1119 | 1407 | 0.21 | Independence, Missouri and Kansas City | 91 | Norfolk County | Massachusetts | 1,025.91 | 396.11 | 670850 | 654 | 1694 | 672107 | 655 | 1697 | 675436 | 658 | 1705 | 3329 | 0.50 | Dedham | 92 | Bernalillo County | New Mexico | 3,006.53 | 1,160.83 | 662564 | 220 | 571 | 664425 | 221 | 572 | 670968 | 223 | 578 | 6543 | 0.98 | Albuquerque | 93 | Jefferson County | Alabama | 2,878.19 | 1,111.28 | 658466 | 229 | 593 | 658386 | 229 | 592 | 658931 | 229 | 593 | 545 | 0.08 | Birmingham | 94 | Hudson County | New Jersey | 119.63 | 46.19 | 634266 | 5302 | 13732 | 634979 | 5308 | 13747 | 641224 | 5360 | 13882 | 6245 | 0.98 | Jersey City | 95 | El Paso County | Colorado | 5,508.39 | 2,126.80 | 622263 | 113 | 293 | 627159 | 114 | 295 | 636963 | 116 | 299 | 9804 | 1.56 | Colorado Springs | 96 | Davidson County | Tennessee | 1,305.44 | 504.03 | 626681 | 480 | 1243 | 628053 | 481 | 1246 | 635475 | 487 | 1261 | 7422 | 1.18 | Nashville | 97 | Lee County | Florida | 2,031.88 | 784.51 | 618754 | 305 | 789 | 620450 | 305 | 791 | 631330 | 311 | 805 | 10880 | 1.75 | Fort Myers | 98 | Monmouth County | New Jersey | 1,214.17 | 468.79 | 630380 | 519 | 1345 | 630920 | 520 | 1346 | 631020 | 520 | 1346 | 100 | 0.02 | Freehold | 99 | Bucks County | Pennsylvania | 1,565.15 | 604.31 | 625249 | 399 | 1035 | 625618 | 400 | 1035 | 626854 | 401 | 1037 | 1236 | 0.20 | Doylestown | 100 | Providence County | Rhode Island | 1,060.60 | 409.50 | 626667 | 591 | 1530 | 626797 | 591 | 1531 | 626709 | 591 | 1530 | -88 | -0.01 | Providence