| # | County | State | Population | Change since 2020 | Unemployment rate |
| 1 | Baca County | Colorado | 3,367 | -4.1 % | 3.2 % |
| 2 | Bacon County | Georgia | 11,045 | -0.9 % | 3.3 % |
| 3 | Bailey County | Texas | 7,031 | 1.9 % | 4.1 % |
| 4 | Baker County | Florida | 29,325 | 3.8 % | 4.2 % |
| 5 | Baker County | Oregon | 16,750 | 0.5 % | 5.5 % |
| 6 | Baker County | Georgia | 2,732 | -4.9 % | 4.4 % |
| 7 | Baldwin County | Alabama | 261,608 | 12.9 % | 2.5 % |
| 8 | Baldwin County | Georgia | 43,644 | -0.3 % | 3.8 % |
| 9 | Ballard County | Kentucky | 7,626 | -1.4 % | 5.0 % |
| 10 | Baltimore city | Maryland | 568,271 | -3.0 % | 5.2 % |
| 11 | Baltimore County | Maryland | 852,425 | -0.2 % | 4.0 % |
| 12 | Bamberg County | South Carolina | 12,870 | -3.3 % | 5.9 % |
| 13 | Bandera County | Texas | 22,830 | 9.5 % | 4.0 % |
| 14 | Banks County | Georgia | 20,318 | 12.3 % | 2.9 % |
| 15 | Banner County | Nebraska | 665 | -1.5 % | 3.3 % |
| 16 | Bannock County | Idaho | 91,010 | 4.6 % | 4.0 % |
| 17 | Baraga County | Michigan | 8,169 | 0.2 % | 7.6 % |
| 18 | Barber County | Kansas | 4,070 | -3.9 % | 3.2 % |
| 19 | Barbour County | Alabama | 24,358 | -3.4 % | 3.6 % |
| 20 | Barbour County | West Virginia | 15,369 | -0.6 % | 5.2 % |
| 21 | Barnes County | North Dakota | 10,798 | -0.4 % | 3.0 % |
| 22 | Barnstable County | Massachusetts | 232,570 | 1.5 % | 5.2 % |
| 23 | Barnwell County | South Carolina | 20,495 | -0.5 % | 5.8 % |
| 24 | Barren County | Kentucky | 45,609 | 2.5 % | 4.9 % |
| 25 | Barron County | Wisconsin | 46,810 | 0.2 % | 4.0 % |
| 26 | Barrow County | Georgia | 96,294 | 15.3 % | 2.9 % |
| 27 | Barry County | Michigan | 64,025 | 2.6 % | 5.0 % |
| 28 | Barry County | Missouri | 35,618 | 3.2 % | 4.4 % |
| 29 | Bartholomew County | Indiana | 84,741 | 3.1 % | 3.6 % |
| 30 | Barton County | Kansas | 24,835 | -2.6 % | 3.7 % |
| 31 | Barton County | Missouri | 11,717 | 0.7 % | 4.1 % |
| 32 | Bartow County | Georgia | 117,508 | 7.9 % | 3.2 % |
| 33 | Bastrop County | Texas | 114,931 | 18.2 % | 3.7 % |
| 34 | Bates County | Missouri | 16,394 | 2.2 % | 4.0 % |
| 35 | Bath County | Kentucky | 12,951 | 1.6 % | 6.2 % |
| 36 | Bath County | Virginia | 4,071 | -3.2 % | 2.7 % |
| 37 | Baxter County | Arkansas | 43,007 | 3.3 % | 4.4 % |
| 38 | Bay County | Florida | 199,718 | 14.0 % | 4.0 % |
| 39 | Bay County | Michigan | 102,651 | -1.2 % | 6.1 % |
| 40 | Bayfield County | Wisconsin | 16,838 | 3.8 % | 4.6 % |
| 41 | Baylor County | Texas | 3,533 | 2.0 % | 3.0 % |
| 42 | Beadle County | South Dakota | 19,459 | 1.6 % | 2.0 % |
| 43 | Bear Lake County | Idaho | 6,779 | 6.4 % | 3.0 % |
| 44 | Beaufort County | South Carolina | 201,775 | 7.8 % | 4.2 % |
| 45 | Beaufort County | North Carolina | 44,576 | -0.2 % | 3.5 % |
| 46 | Beauregard Parish | Louisiana | 36,695 | 0.4 % | 4.3 % |
| 47 | Beaver County | Pennsylvania | 165,540 | -1.6 % | 4.5 % |
| 48 | Beaver County | Utah | 7,424 | 5.0 % | 3.0 % |
| 49 | Beaver County | Oklahoma | 5,025 | -0.5 % | 2.6 % |
| 50 | Beaverhead County | Montana | 10,006 | 6.8 % | 2.8 % |
| 51 | Becker County | Minnesota | 35,444 | 0.7 % | 4.5 % |
| 52 | Beckham County | Oklahoma | 22,248 | -0.7 % | 3.3 % |
| 53 | Bedford County | Virginia | 82,182 | 3.4 % | 3.3 % |
| 54 | Bedford County | Tennessee | 54,228 | 7.9 % | 3.4 % |
| 55 | Bedford County | Pennsylvania | 47,643 | 0.1 % | 4.4 % |
| 56 | Bee County | Texas | 31,226 | 0.6 % | 4.8 % |
| 57 | Belknap County | New Hampshire | 65,257 | 2.4 % | 3.0 % |
| 58 | Bell County | Texas | 399,578 | 7.8 % | 4.6 % |
| 59 | Bell County | Kentucky | 23,051 | -4.3 % | 6.2 % |
| 60 | Belmont County | Ohio | 64,692 | -2.7 % | 5.6 % |
| 61 | Beltrami County | Minnesota | 46,762 | 1.2 % | 5.1 % |
| 62 | Ben Hill County | Georgia | 16,945 | -1.4 % | 4.0 % |
| 63 | Benewah County | Idaho | 10,529 | 10.5 % | 5.6 % |
| 64 | Bennett County | South Dakota | 3,289 | -2.7 % | 2.6 % |
| 65 | Bennington County | Vermont | 37,039 | -0.8 % | 3.1 % |
| 66 | Benson County | North Dakota | 5,756 | -3.4 % | 3.5 % |
| 67 | Bent County | Colorado | 5,779 | 2.3 % | 4.6 % |
| 68 | Benton County | Arkansas | 321,566 | 13.1 % | 3.2 % |
| 69 | Benton County | Washington | 218,190 | 5.5 % | 4.7 % |
| 70 | Benton County | Oregon | 98,899 | 3.9 % | 4.3 % |
| 71 | Benton County | Minnesota | 41,881 | 1.2 % | 4.7 % |
| 72 | Benton County | Iowa | 25,799 | 0.8 % | 3.3 % |
| 73 | Benton County | Missouri | 20,614 | 6.3 % | 5.4 % |
| 74 | Benton County | Tennessee | 16,173 | 1.9 % | 4.6 % |
| 75 | Benton County | Indiana | 8,853 | 1.7 % | 3.2 % |
| 76 | Benton County | Mississippi | 7,566 | -1.1 % | 4.0 % |
| 77 | Benzie County | Michigan | 18,520 | 3.1 % | 5.7 % |
| 78 | Bergen County | New Jersey | 978,641 | 2.4 % | 4.3 % |
| 79 | Berkeley County | South Carolina | 264,276 | 15.0 % | 4.0 % |
| 80 | Berkeley County | West Virginia | 136,287 | 11.6 % | 3.6 % |
| 81 | Berks County | Pennsylvania | 439,117 | 2.4 % | 4.4 % |
| 82 | Berkshire County | Massachusetts | 128,726 | -0.2 % | 4.4 % |
| 83 | Bernalillo County | New Mexico | 671,747 | -0.7 % | 3.9 % |
| 84 | Berrien County | Michigan | 152,703 | -1.2 % | 5.3 % |
| 85 | Berrien County | Georgia | 18,666 | 2.8 % | 3.5 % |
| 86 | Bertie County | North Carolina | 16,939 | -5.5 % | 4.8 % |
| 87 | Bethel Census Area | Alaska | 18,237 | -2.3 % | 12.0 % |
| 88 | Bexar County | Texas | 2,127,737 | 5.9 % | 4.0 % |
| 89 | Bibb County | Georgia | 157,056 | -0.2 % | 4.3 % |
| 90 | Bibb County | Alabama | 22,258 | -0.1 % | 2.7 % |
| 91 | Bienville Parish | Louisiana | 12,412 | -4.4 % | 5.3 % |
| 92 | Big Horn County | Montana | 12,796 | -2.5 % | 5.8 % |
| 93 | Big Horn County | Wyoming | 12,084 | 4.9 % | 4.2 % |
| 94 | Big Stone County | Minnesota | 5,067 | -2.0 % | 4.2 % |
| 95 | Billings County | North Dakota | 1,063 | 12.2 % | 2.2 % |
| 96 | Bingham County | Idaho | 50,889 | 6.1 % | 3.5 % |
| 97 | Black Hawk County | Iowa | 132,348 | 0.9 % | 4.1 % |
| 98 | Blackford County | Indiana | 11,816 | -2.4 % | 4.1 % |
| 99 | Bladen County | North Carolina | 29,777 | 0.5 % | 5.3 % |
| 100 | Blaine County | Idaho | 25,261 | 4.1 % | 3.2 % |
| 101 | Blaine County | Oklahoma | 8,573 | -1.8 % | 3.1 % |
| 102 | Blaine County | Montana | 6,903 | -1.9 % | 3.0 % |
| 103 | Blaine County | Nebraska | 454 | 5.8 % | 2.8 % |
| 104 | Blair County | Pennsylvania | 120,269 | -2.1 % | 4.1 % |
| 105 | Blanco County | Texas | 13,358 | 17.4 % | 3.5 % |
| 106 | Bland County | Virginia | 6,186 | -1.4 % | 3.8 % |
| 107 | Bleckley County | Georgia | 12,626 | 0.3 % | 3.6 % |
| 108 | Bledsoe County | Tennessee | 15,591 | 4.5 % | 3.3 % |
| 109 | Blount County | Tennessee | 142,211 | 5.1 % | 3.0 % |
| 110 | Blount County | Alabama | 60,163 | 1.7 % | 2.4 % |
| 111 | Blue Earth County | Minnesota | 70,700 | 2.3 % | 3.4 % |
| 112 | Boise County | Idaho | 8,581 | 12.7 % | 4.2 % |
| 113 | Bolivar County | Mississippi | 28,395 | -8.4 % | 4.8 % |
| 114 | Bollinger County | Missouri | 10,610 | 0.4 % | 3.9 % |
| 115 | Bon Homme County | South Dakota | 7,071 | 1.1 % | 2.1 % |
| 116 | Bond County | Illinois | 16,576 | -1.9 % | 4.2 % |
| 117 | Bonner County | Idaho | 53,955 | 14.5 % | 5.4 % |
| 118 | Bonneville County | Idaho | 133,644 | 7.8 % | 3.1 % |
| 119 | Boone County | Missouri | 192,154 | 4.7 % | 3.4 % |
| 120 | Boone County | Kentucky | 144,135 | 6.0 % | 3.9 % |
| 121 | Boone County | Indiana | 78,773 | 11.3 % | 2.8 % |
| 122 | Boone County | Illinois | 53,313 | -0.2 % | 5.5 % |
| 123 | Boone County | Arkansas | 38,636 | 3.4 % | 4.0 % |
| 124 | Boone County | Iowa | 26,729 | 0.1 % | 3.1 % |
| 125 | Boone County | West Virginia | 20,496 | -6.0 % | 5.2 % |
| 126 | Boone County | Nebraska | 5,354 | -0.4 % | 2.2 % |
| 127 | Borden County | Texas | 557 | -11.4 % | 3.3 % |
| 128 | Bosque County | Texas | 19,013 | 4.3 % | 4.0 % |
| 129 | Bossier Parish | Louisiana | 131,102 | 1.8 % | 3.8 % |
| 130 | Botetourt County | Virginia | 34,129 | 1.6 % | 2.9 % |
| 131 | Bottineau County | North Dakota | 6,391 | 0.3 % | 3.0 % |
| 132 | Boulder County | Colorado | 330,262 | -0.2 % | 4.0 % |
| 133 | Boundary County | Idaho | 14,040 | 16.4 % | 5.4 % |
| 134 | Bourbon County | Kentucky | 20,333 | 0.4 % | 4.0 % |
| 135 | Bourbon County | Kansas | 14,424 | 0.5 % | 5.4 % |
| 136 | Bowie County | Texas | 91,992 | -1.0 % | 4.2 % |
| 137 | Bowman County | North Dakota | 2,886 | -3.6 % | 1.8 % |
| 138 | Box Butte County | Nebraska | 10,703 | -1.2 % | 3.1 % |
| 139 | Box Elder County | Utah | 64,120 | 11.2 % | 3.4 % |
| 140 | Boyd County | Kentucky | 47,777 | -1.0 % | 5.5 % |
| 141 | Boyd County | Nebraska | 1,700 | -6.1 % | 3.2 % |
| 142 | Boyle County | Kentucky | 31,394 | 2.5 % | 4.9 % |
| 143 | Bracken County | Kentucky | 8,497 | 1.1 % | 5.5 % |
| 144 | Bradford County | Pennsylvania | 59,699 | -0.4 % | 4.2 % |
| 145 | Bradford County | Florida | 28,075 | -0.8 % | 4.5 % |
| 146 | Bradley County | Tennessee | 113,782 | 4.8 % | 3.8 % |
| 147 | Bradley County | Arkansas | 9,935 | -5.8 % | 6.4 % |
| 148 | Branch County | Michigan | 46,187 | 2.9 % | 4.5 % |
| 149 | Brantley County | Georgia | 18,795 | 4.3 % | 3.1 % |
| 150 | Braxton County | West Virginia | 12,051 | -3.2 % | 4.6 % |
| 151 | Brazoria County | Texas | 413,224 | 11.1 % | 4.6 % |
| 152 | Brazos County | Texas | 249,624 | 6.7 % | 3.6 % |
| 153 | Breathitt County | Kentucky | 12,804 | -6.7 % | 6.5 % |
| 154 | Breckinridge County | Kentucky | 21,221 | 3.9 % | 5.3 % |
| 155 | Bremer County | Iowa | 25,328 | 1.4 % | 3.3 % |
| 156 | Brevard County | Florida | 658,447 | 8.5 % | 4.2 % |
| 157 | Brewster County | Texas | 9,508 | -0.4 % | 3.0 % |
| 158 | Briscoe County | Texas | 1,494 | 4.0 % | 3.4 % |
| 159 | Bristol Bay Borough | Alaska | 884 | 4.9 % | 3.7 % |
| 160 | Bristol city | Virginia | 16,316 | -5.3 % | 3.8 % |
| 161 | Bristol County | Massachusetts | 588,593 | 1.6 % | 5.1 % |
| 162 | Bristol County | Rhode Island | 50,145 | -1.3 % | 3.6 % |
| 163 | Broadwater County | Montana | 8,302 | 22.5 % | 2.7 % |
| 164 | Bronx County | New York | 1,384,724 | -6.0 % | 7.0 % |
| 165 | Brooke County | West Virginia | 21,285 | -5.6 % | 4.9 % |
| 166 | Brookings County | South Dakota | 36,359 | 5.8 % | 2.1 % |
| 167 | Brooks County | Georgia | 16,344 | 0.3 % | 3.7 % |
| 168 | Brooks County | Texas | 6,740 | -5.4 % | 4.2 % |
| 169 | Broome County | New York | 196,397 | -1.2 % | 4.2 % |
| 170 | Broomfield County | Colorado | 78,323 | 5.7 % | 3.8 % |
| 171 | Broward County | Florida | 2,037,472 | 4.8 % | 3.7 % |
| 172 | Brown County | Wisconsin | 273,909 | 1.9 % | 2.9 % |
| 173 | Brown County | Ohio | 44,292 | 1.4 % | 5.3 % |
| 174 | Brown County | Texas | 38,631 | 1.4 % | 3.9 % |
| 175 | Brown County | South Dakota | 37,495 | -2.1 % | 2.1 % |
| 176 | Brown County | Minnesota | 25,710 | -0.8 % | 3.9 % |
| 177 | Brown County | Indiana | 15,650 | 1.2 % | 3.4 % |
| 178 | Brown County | Kansas | 9,142 | -3.8 % | 4.4 % |
| 179 | Brown County | Illinois | 6,307 | 0.9 % | 3.1 % |
| 180 | Brown County | Nebraska | 2,877 | -0.9 % | 2.2 % |
| 181 | Brule County | South Dakota | 5,261 | 0.3 % | 1.4 % |
| 182 | Brunswick County | North Carolina | 167,112 | 22.3 % | 4.3 % |
| 183 | Brunswick County | Virginia | 15,750 | -0.6 % | 4.9 % |
| 184 | Bryan County | Georgia | 51,105 | 14.2 % | 2.8 % |
| 185 | Bryan County | Oklahoma | 50,305 | 9.2 % | 3.6 % |
| 186 | Buchanan County | Missouri | 83,574 | -1.4 % | 4.2 % |
| 187 | Buchanan County | Iowa | 20,733 | 0.8 % | 3.5 % |
| 188 | Buchanan County | Virginia | 18,632 | -8.4 % | 5.6 % |
| 189 | Buckingham County | Virginia | 17,115 | 1.7 % | 3.8 % |
| 190 | Bucks County | Pennsylvania | 650,131 | 0.6 % | 3.8 % |
| 191 | Buena Vista city | Virginia | 6,581 | -0.9 % | 3.5 % |
| 192 | Buena Vista County | Iowa | 20,816 | -0.0 % | 3.0 % |
| 193 | Buffalo County | Nebraska | 51,156 | 2.1 % | 2.5 % |
| 194 | Buffalo County | Wisconsin | 13,464 | 1.1 % | 4.0 % |
| 195 | Buffalo County | South Dakota | 1,825 | -6.2 % | 4.4 % |
| 196 | Bullitt County | Kentucky | 85,802 | 4.4 % | 4.5 % |
| 197 | Bulloch County | Georgia | 85,454 | 7.3 % | 3.5 % |
| 198 | Bullock County | Alabama | 9,901 | -4.4 % | 3.4 % |
| 199 | Buncombe County | North Carolina | 279,210 | 3.6 % | 4.8 % |
| 200 | Bureau County | Illinois | 32,486 | -2.4 % | 5.2 % |
| 201 | Burke County | North Carolina | 88,545 | 1.1 % | 3.9 % |
| 202 | Burke County | Georgia | 24,472 | -0.5 % | 4.6 % |
| 203 | Burke County | North Dakota | 2,154 | -1.9 % | 2.2 % |
| 204 | Burleigh County | North Dakota | 103,107 | 4.7 % | 2.4 % |
| 205 | Burleson County | Texas | 20,179 | 14.4 % | 3.6 % |
| 206 | Burlington County | New Jersey | 475,515 | 3.0 % | 4.8 % |
| 207 | Burnet County | Texas | 55,722 | 13.4 % | 3.6 % |
| 208 | Burnett County | Wisconsin | 17,187 | 4.0 % | 5.0 % |
| 209 | Burt County | Nebraska | 6,727 | -0.0 % | 3.4 % |
| 210 | Butler County | Ohio | 399,542 | 2.4 % | 4.6 % |
| 211 | Butler County | Pennsylvania | 199,341 | 2.9 % | 3.8 % |
| 212 | Butler County | Kansas | 69,158 | 2.7 % | 3.8 % |
| 213 | Butler County | Missouri | 41,814 | -0.7 % | 5.2 % |
| 214 | Butler County | Alabama | 18,256 | -4.2 % | 3.5 % |
| 215 | Butler County | Iowa | 14,156 | -1.3 % | 3.9 % |
| 216 | Butler County | Kentucky | 12,551 | 1.5 % | 5.1 % |
| 217 | Butler County | Nebraska | 8,439 | 0.8 % | 2.4 % |
| 218 | Butte County | California | 208,334 | -1.6 % | 6.2 % |
| 219 | Butte County | South Dakota | 10,891 | 6.3 % | 1.9 % |
| 220 | Butte County | Idaho | 2,735 | 6.2 % | 4.0 % |
| 221 | Butts County | Georgia | 27,127 | 6.6 % | 3.3 % |