(Links below lead to Quick Facts for Wyoming Counties: People, Business & Geography at U.S. Census Bureau.)
| Area | 7/1/2008 | 7/1/2007 | 7/1/2006 | 7/1/2005 | 7/1/2004 | 7/1/2003 | 7/1/2002 | 7/1/2001 | 7/1/2000 | Census 2000 |
| Wyoming | 532,668 | 523,252 | 512,573 | 506,007 | 502,816 | 499,056 | 496,969 | 492,924 | 493,963 | 493,782 |
|---|---|---|---|---|---|---|---|---|---|---|
| Albany County | 32,758 | 32,288 | 32,613 | 32,507 | 32,681 | 32,436 | 32,249 | 32,201 | 31,913 | 32,014 |
| Big Horn County | 11,322 | 11,215 | 11,099 | 11,107 | 11,184 | 11,055 | 11,163 | 11,224 | 11,411 | 11,461 |
| Campbell County | 41,473 | 40,433 | 38,456 | 37,021 | 36,224 | 36,061 | 35,854 | 34,519 | 33,938 | 33,698 |
| Carbon County | 15,624 | 15,420 | 15,056 | 15,036 | 15,202 | 15,197 | 15,233 | 15,189 | 15,580 | 15,639 |
| Converse County | 13,267 | 12,870 | 12,619 | 12,447 | 12,240 | 12,149 | 12,153 | 11,979 | 12,098 | 12,052 |
| Crook County | 6,457 | 6,313 | 6,075 | 6,013 | 5,927 | 5,887 | 5,865 | 5,747 | 5,897 | 5,887 |
| Fremont County | 38,113 | 37,461 | 36,770 | 36,273 | 35,941 | 35,797 | 35,800 | 35,607 | 35,818 | 35,804 |
| Goshen County | 12,072 | 12,020 | 12,010 | 12,073 | 12,157 | 12,135 | 12,219 | 12,389 | 12,544 | 12,538 |
| Hot Springs County | 4,622 | 4,558 | 4,529 | 4,510 | 4,557 | 4,580 | 4,714 | 4,754 | 4,865 | 4,882 |
| Johnson County | 8,464 | 8,139 | 7,808 | 7,645 | 7,522 | 7,472 | 7,355 | 7,156 | 7,102 | 7,075 |
| Laramie County | 87,542 | 86,480 | 85,890 | 85,304 | 85,210 | 84,289 | 83,135 | 82,380 | 81,748 | 81,607 |
| Lincoln County | 16,631 | 16,172 | 15,741 | 15,348 | 15,093 | 14,788 | 14,643 | 14,588 | 14,614 | 14,573 |
| Natrona County | 73,129 | 71,784 | 70,220 | 69,408 | 68,637 | 67,939 | 67,353 | 66,863 | 66,557 | 66,533 |
| Niobrara County | 2,428 | 2,352 | 2,235 | 2,225 | 2,245 | 2,223 | 2,245 | 2,324 | 2,387 | 2,407 |
| Park County | 27,574 | 27,181 | 26,767 | 26,355 | 26,057 | 25,950 | 25,735 | 25,675 | 25,806 | 25,786 |
| Platte County | 8,294 | 8,387 | 8,437 | 8,472 | 8,570 | 8,578 | 8,702 | 8,738 | 8,748 | 8,807 |
| Sheridan County | 28,662 | 28,037 | 27,477 | 27,140 | 26,997 | 26,969 | 26,872 | 26,647 | 26,591 | 26,560 |
| Sublette County | 8,456 | 7,948 | 7,238 | 6,876 | 6,573 | 6,318 | 6,145 | 5,897 | 5,946 | 5,920 |
| Sweetwater County | 39,944 | 39,376 | 38,001 | 37,308 | 36,883 | 36,576 | 36,838 | 36,568 | 37,483 | 37,613 |
| Teton County | 20,376 | 19,958 | 19,588 | 19,264 | 19,184 | 18,852 | 18,699 | 18,578 | 18,365 | 18,251 |
| Uinta County | 20,617 | 20,155 | 19,688 | 19,429 | 19,418 | 19,439 | 19,565 | 19,405 | 19,662 | 19,742 |
| Washakie County | 7,821 | 7,816 | 7,675 | 7,762 | 7,754 | 7,821 | 7,891 | 8,023 | 8,255 | 8,289 |
| Weston County | 7,022 | 6,889 | 6,581 | 6,484 | 6,560 | 6,545 | 6,541 | 6,473 | 6,635 | 6,644 |
Source: Population Division, U.S. Census Bureau