(Links below lead to Quick Facts for Utah 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 |
| Utah | 2,736,424 | 2,668,925 | 2,585,155 | 2,501,262 | 2,439,852 | 2,380,462 | 2,334,462 | 2,291,066 | 2,244,210 | 2,233,169 |
|---|---|---|---|---|---|---|---|---|---|---|
| Beaver County | 6,162 | 6,061 | 6,090 | 6,072 | 6,000 | 5,997 | 6,047 | 6,006 | 6,016 | 6,005 |
| Box Elder County | 49,015 | 47,793 | 46,695 | 45,925 | 45,561 | 45,213 | 44,511 | 43,623 | 42,871 | 42,745 |
| Cache County | 112,616 | 108,995 | 106,399 | 104,595 | 102,255 | 100,170 | 97,262 | 93,778 | 91,851 | 91,391 |
| Carbon County | 19,549 | 19,608 | 19,188 | 19,185 | 19,444 | 19,668 | 19,745 | 19,691 | 20,354 | 20,422 |
| Daggett County | 938 | 922 | 936 | 921 | 919 | 890 | 892 | 923 | 928 | 921 |
| Davis County | 295,332 | 287,751 | 278,759 | 269,739 | 262,682 | 256,120 | 249,765 | 244,528 | 240,279 | 238,994 |
| Duchesne County | 16,861 | 16,187 | 15,433 | 15,148 | 14,840 | 14,795 | 14,807 | 14,545 | 14,371 | 14,371 |
| Emery County | 10,510 | 10,369 | 10,280 | 10,347 | 10,381 | 10,506 | 10,559 | 10,667 | 10,945 | 10,860 |
| Garfield County | 4,658 | 4,528 | 4,396 | 4,342 | 4,361 | 4,457 | 4,552 | 4,657 | 4,748 | 4,735 |
| Grand County | 9,589 | 9,422 | 9,257 | 9,011 | 8,808 | 8,761 | 8,694 | 8,504 | 8,401 | 8,485 |
| Iron County | 44,540 | 43,453 | 41,746 | 39,333 | 37,056 | 36,077 | 35,657 | 34,730 | 33,992 | 33,779 |
| Juab County | 9,983 | 9,568 | 9,112 | 8,894 | 8,782 | 8,603 | 8,476 | 8,388 | 8,271 | 8,238 |
| Kane County | 6,577 | 6,506 | 6,395 | 6,178 | 6,046 | 6,012 | 5,997 | 5,951 | 6,079 | 6,046 |
| Millard County | 12,082 | 11,898 | 11,893 | 11,872 | 11,975 | 12,142 | 12,219 | 12,297 | 12,394 | 12,405 |
| Morgan County | 8,669 | 8,335 | 8,017 | 7,762 | 7,557 | 7,449 | 7,403 | 7,290 | 7,155 | 7,129 |
| Piute County | 1,404 | 1,336 | 1,338 | 1,362 | 1,374 | 1,365 | 1,387 | 1,397 | 1,431 | 1,435 |
| Rich County | 2,205 | 2,089 | 2,006 | 2,011 | 2,018 | 2,014 | 1,934 | 1,925 | 1,964 | 1,961 |
| Salt Lake County | 1,022,651 | 1,005,245 | 987,035 | 961,098 | 948,909 | 936,714 | 924,515 | 914,237 | 901,004 | 898,387 |
| San Juan County | 15,055 | 14,457 | 13,998 | 13,891 | 13,933 | 13,733 | 13,782 | 13,585 | 14,373 | 14,413 |
| Sanpete County | 25,520 | 24,578 | 23,954 | 23,747 | 23,530 | 23,344 | 23,229 | 23,141 | 22,805 | 22,763 |
| Sevier County | 20,014 | 19,643 | 19,288 | 19,041 | 19,107 | 18,960 | 18,948 | 18,911 | 18,868 | 18,842 |
| Summit County | 36,100 | 35,377 | 34,867 | 34,659 | 33,683 | 32,653 | 31,753 | 30,924 | 29,987 | 29,736 |
| Tooele County | 56,941 | 54,740 | 52,352 | 50,148 | 48,714 | 47,369 | 45,610 | 43,739 | 41,615 | 40,735 |
| Uintah County | 29,885 | 28,978 | 27,818 | 26,975 | 26,464 | 26,179 | 26,174 | 25,697 | 25,252 | 25,224 |
| Utah County | 530,837 | 513,263 | 482,047 | 454,839 | 434,114 | 409,572 | 397,281 | 387,824 | 371,635 | 368,536 |
| Wasatch County | 21,066 | 20,442 | 19,861 | 18,747 | 17,843 | 17,391 | 16,741 | 16,091 | 15,416 | 15,215 |
| Washington County | 137,589 | 133,447 | 127,073 | 119,076 | 110,253 | 104,245 | 99,412 | 94,613 | 91,254 | 90,354 |
| Wayne County | 2,589 | 2,515 | 2,477 | 2,409 | 2,426 | 2,465 | 2,520 | 2,510 | 2,529 | 2,509 |
| Weber County | 227,487 | 221,419 | 216,445 | 213,935 | 210,817 | 207,598 | 204,590 | 200,894 | 197,422 | 196,533 |
Source: Population Division, U.S. Census Bureau