| # | County | State | Population | Change since 2020 | Unemployment rate |
| 1 | Jack County | Texas | 9,398 | 10.9 % | 5.4 % |
| 2 | Jackson County | Missouri | 727,362 | 1.4 % | 4.2 % |
| 3 | Jackson County | Oregon | 221,331 | -0.9 % | 5.7 % |
| 4 | Jackson County | Michigan | 160,233 | -0.1 % | 5.4 % |
| 5 | Jackson County | Mississippi | 147,002 | 2.6 % | 3.7 % |
| 6 | Jackson County | Georgia | 93,825 | 23.6 % | 3.0 % |
| 7 | Jackson County | Alabama | 53,780 | 2.3 % | 3.3 % |
| 8 | Jackson County | Illinois | 53,199 | -0.3 % | 4.8 % |
| 9 | Jackson County | Florida | 49,980 | 5.6 % | 4.5 % |
| 10 | Jackson County | Indiana | 47,420 | 2.1 % | 3.2 % |
| 11 | Jackson County | North Carolina | 45,281 | 5.0 % | 3.5 % |
| 12 | Jackson County | Ohio | 32,723 | 0.2 % | 5.9 % |
| 13 | Jackson County | West Virginia | 27,718 | -0.3 % | 5.6 % |
| 14 | Jackson County | Oklahoma | 24,541 | -1.0 % | 2.7 % |
| 15 | Jackson County | Wisconsin | 21,027 | -0.5 % | 4.1 % |
| 16 | Jackson County | Iowa | 19,390 | -0.5 % | 4.1 % |
| 17 | Jackson County | Arkansas | 16,673 | -0.5 % | 4.7 % |
| 18 | Jackson County | Texas | 15,284 | 2.0 % | 4.3 % |
| 19 | Jackson County | Kansas | 13,525 | 2.2 % | 3.3 % |
| 20 | Jackson County | Kentucky | 13,358 | 3.1 % | 7.1 % |
| 21 | Jackson County | Tennessee | 12,376 | 6.6 % | 4.2 % |
| 22 | Jackson County | Minnesota | 9,861 | -1.3 % | 4.1 % |
| 23 | Jackson County | South Dakota | 2,737 | -2.5 % | 3.3 % |
| 24 | Jackson County | Colorado | 1,273 | -7.8 % | 3.3 % |
| 25 | Jackson Parish | Louisiana | 14,797 | -1.6 % | 4.8 % |
| 26 | James City County | Virginia | 82,797 | 5.8 % | 3.4 % |
| 27 | Jasper County | Missouri | 126,479 | 3.0 % | 3.8 % |
| 28 | Jasper County | Iowa | 38,107 | 0.8 % | 3.6 % |
| 29 | Jasper County | South Carolina | 35,618 | 23.7 % | 4.4 % |
| 30 | Jasper County | Indiana | 33,387 | 1.4 % | 3.9 % |
| 31 | Jasper County | Texas | 32,907 | -0.2 % | 6.1 % |
| 32 | Jasper County | Georgia | 17,219 | 18.0 % | 3.4 % |
| 33 | Jasper County | Mississippi | 15,799 | -3.5 % | 4.0 % |
| 34 | Jasper County | Illinois | 9,092 | -2.2 % | 3.6 % |
| 35 | Jay County | Indiana | 20,164 | -1.5 % | 3.4 % |
| 36 | Jeff Davis County | Georgia | 15,119 | 2.3 % | 4.4 % |
| 37 | Jeff Davis County | Texas | 1,778 | -11.0 % | 4.4 % |
| 38 | Jefferson County | Kentucky | 793,881 | 1.4 % | 4.5 % |
| 39 | Jefferson County | Alabama | 664,744 | -1.4 % | 2.9 % |
| 40 | Jefferson County | Colorado | 578,533 | -0.8 % | 3.8 % |
| 41 | Jefferson County | Texas | 253,948 | -1.0 % | 5.7 % |
| 42 | Jefferson County | Missouri | 231,888 | 2.3 % | 3.7 % |
| 43 | Jefferson County | New York | 113,140 | -3.1 % | 4.5 % |
| 44 | Jefferson County | Wisconsin | 86,245 | 0.1 % | 2.9 % |
| 45 | Jefferson County | Ohio | 63,900 | -2.1 % | 5.8 % |
| 46 | Jefferson County | Arkansas | 63,672 | -5.3 % | 6.0 % |
| 47 | Jefferson County | West Virginia | 61,264 | 6.2 % | 3.1 % |
| 48 | Jefferson County | Tennessee | 59,217 | 8.3 % | 3.7 % |
| 49 | Jefferson County | Pennsylvania | 43,367 | -2.5 % | 4.6 % |
| 50 | Jefferson County | Illinois | 36,107 | -2.7 % | 4.9 % |
| 51 | Jefferson County | Idaho | 34,854 | 12.8 % | 2.9 % |
| 52 | Jefferson County | Washington | 33,944 | 3.0 % | 5.1 % |
| 53 | Jefferson County | Indiana | 32,921 | -0.7 % | 3.7 % |
| 54 | Jefferson County | Oregon | 25,536 | 4.2 % | 5.6 % |
| 55 | Jefferson County | Kansas | 18,332 | -0.2 % | 3.5 % |
| 56 | Jefferson County | Florida | 15,921 | 9.7 % | 3.7 % |
| 57 | Jefferson County | Iowa | 15,781 | 0.7 % | 3.6 % |
| 58 | Jefferson County | Georgia | 15,019 | -4.4 % | 4.2 % |
| 59 | Jefferson County | Montana | 13,304 | 10.1 % | 3.0 % |
| 60 | Jefferson County | Nebraska | 7,136 | -1.4 % | 3.1 % |
| 61 | Jefferson County | Mississippi | 6,900 | -4.9 % | 10.4 % |
| 62 | Jefferson County | Oklahoma | 5,374 | 0.6 % | 4.9 % |
| 63 | Jefferson Davis County | Mississippi | 11,059 | -2.4 % | 3.8 % |
| 64 | Jefferson Davis Parish | Louisiana | 31,436 | -2.5 % | 4.6 % |
| 65 | Jefferson Parish | Louisiana | 427,253 | -3.1 % | 4.0 % |
| 66 | Jenkins County | Georgia | 8,836 | 1.9 % | 3.2 % |
| 67 | Jennings County | Indiana | 27,634 | 0.1 % | 3.6 % |
| 68 | Jerauld County | South Dakota | 1,689 | 1.9 % | 1.7 % |
| 69 | Jerome County | Idaho | 26,056 | 7.5 % | 3.3 % |
| 70 | Jersey County | Illinois | 21,150 | -1.7 % | 3.8 % |
| 71 | Jessamine County | Kentucky | 56,495 | 6.6 % | 4.0 % |
| 72 | Jewell County | Kansas | 2,899 | -1.1 % | 4.6 % |
| 73 | Jim Hogg County | Texas | 4,583 | -5.2 % | 4.9 % |
| 74 | Jim Wells County | Texas | 38,886 | -0.0 % | 5.1 % |
| 75 | Jo Daviess County | Illinois | 21,528 | -2.5 % | 3.8 % |
| 76 | Johnson County | Kansas | 632,276 | 3.7 % | 3.5 % |
| 77 | Johnson County | Texas | 210,547 | 17.0 % | 3.7 % |
| 78 | Johnson County | Indiana | 170,614 | 5.5 % | 3.1 % |
| 79 | Johnson County | Iowa | 160,080 | 4.7 % | 2.7 % |
| 80 | Johnson County | Missouri | 55,880 | 3.5 % | 4.0 % |
| 81 | Johnson County | Arkansas | 26,172 | 1.6 % | 5.3 % |
| 82 | Johnson County | Kentucky | 22,098 | -2.6 % | 6.4 % |
| 83 | Johnson County | Tennessee | 18,506 | 3.1 % | 5.3 % |
| 84 | Johnson County | Illinois | 13,320 | 0.1 % | 5.0 % |
| 85 | Johnson County | Georgia | 9,178 | -0.1 % | 3.4 % |
| 86 | Johnson County | Wyoming | 8,803 | 4.2 % | 2.8 % |
| 87 | Johnson County | Nebraska | 5,219 | -1.3 % | 3.9 % |
| 88 | Johnston County | North Carolina | 249,794 | 15.6 % | 3.2 % |
| 89 | Johnston County | Oklahoma | 10,293 | 0.2 % | 4.4 % |
| 90 | Jones County | Mississippi | 65,837 | -2.1 % | 3.1 % |
| 91 | Jones County | Georgia | 29,047 | 2.5 % | 3.4 % |
| 92 | Jones County | Iowa | 21,116 | 2.3 % | 4.2 % |
| 93 | Jones County | Texas | 20,850 | 6.0 % | 3.5 % |
| 94 | Jones County | North Carolina | 9,462 | 3.2 % | 4.1 % |
| 95 | Jones County | South Dakota | 874 | -4.7 % | 2.6 % |
| 96 | Josephine County | Oregon | 88,276 | 0.2 % | 7.1 % |
| 97 | Juab County | Utah | 13,297 | 12.8 % | 3.5 % |
| 98 | Judith Basin County | Montana | 2,111 | 4.6 % | 3.3 % |
| 99 | Juneau City and Borough | Alaska | 31,572 | -2.1 % | 3.4 % |
| 100 | Juneau County | Wisconsin | 26,590 | -0.5 % | 3.6 % |
| 101 | Juniata County | Pennsylvania | 23,395 | -0.5 % | 5.2 % |