(Links below lead to Quick Facts for Utah Counties: People, Business & Geography at U.S. Census Bureau.)
| Area | 7/1/2009 | 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 | 2,784,572 | 2,727,343 | 2,663,796 | 2,583,724 | 2,499,637 | 2,438,915 | 2,379,938 | 2,334,473 | 2,291,250 | 2,244,314 | 2,233,169 |
|---|---|---|---|---|---|---|---|---|---|---|---|
| Beaver County | 6,267 | 6,182 | 6,068 | 6,113 | 6,067 | 5,994 | 5,990 | 6,040 | 6,003 | 6,016 | 6,005 |
| Box Elder County | 49,902 | 49,059 | 47,863 | 46,722 | 45,938 | 45,575 | 45,229 | 44,522 | 43,632 | 42,872 | 42,745 |
| Cache County | 115,269 | 111,873 | 108,655 | 106,399 | 104,540 | 102,229 | 100,177 | 97,277 | 93,798 | 91,872 | 91,391 |
| Carbon County | 19,989 | 19,605 | 19,666 | 19,242 | 19,180 | 19,438 | 19,665 | 19,745 | 19,691 | 20,354 | 20,422 |
| Daggett County | 941 | 912 | 904 | 924 | 916 | 914 | 887 | 888 | 921 | 928 | 921 |
| Davis County | 300,827 | 295,061 | 287,888 | 279,037 | 269,695 | 262,689 | 256,173 | 249,835 | 244,578 | 240,293 | 238,994 |
| Duchesne County | 17,948 | 16,926 | 16,191 | 15,436 | 15,135 | 14,827 | 14,782 | 14,796 | 14,540 | 14,371 | 14,371 |
| Emery County | 10,629 | 10,470 | 10,344 | 10,264 | 10,331 | 10,369 | 10,497 | 10,553 | 10,665 | 10,946 | 10,860 |
| Garfield County | 4,625 | 4,600 | 4,499 | 4,376 | 4,339 | 4,359 | 4,457 | 4,550 | 4,657 | 4,748 | 4,735 |
| Grand County | 9,660 | 9,598 | 9,422 | 9,291 | 9,066 | 8,851 | 8,793 | 8,716 | 8,515 | 8,399 | 8,485 |
| Iron County | 45,280 | 44,194 | 43,283 | 41,703 | 39,298 | 37,030 | 36,061 | 35,648 | 34,724 | 33,989 | 33,779 |
| Juab County | 10,244 | 9,999 | 9,551 | 9,132 | 8,889 | 8,777 | 8,599 | 8,473 | 8,386 | 8,271 | 8,238 |
| Kane County | 6,601 | 6,541 | 6,494 | 6,430 | 6,167 | 6,038 | 6,007 | 5,994 | 5,951 | 6,079 | 6,046 |
| Millard County | 12,276 | 12,095 | 11,886 | 11,889 | 11,891 | 11,988 | 12,151 | 12,222 | 12,300 | 12,395 | 12,405 |
| Morgan County | 8,908 | 8,744 | 8,438 | 8,062 | 7,752 | 7,551 | 7,444 | 7,400 | 7,289 | 7,155 | 7,129 |
| Piute County | 1,431 | 1,406 | 1,329 | 1,350 | 1,362 | 1,374 | 1,365 | 1,387 | 1,397 | 1,431 | 1,435 |
| Rich County | 2,160 | 2,141 | 2,053 | 1,977 | 2,005 | 2,012 | 2,007 | 1,928 | 1,921 | 1,964 | 1,961 |
| Salt Lake County | 1,034,989 | 1,018,527 | 1,002,425 | 985,487 | 960,067 | 948,223 | 936,378 | 924,534 | 914,334 | 901,051 | 898,387 |
| San Juan County | 15,049 | 14,868 | 14,378 | 13,964 | 13,887 | 13,928 | 13,727 | 13,776 | 13,583 | 14,373 | 14,413 |
| Sanpete County | 25,946 | 25,514 | 24,565 | 23,967 | 23,717 | 23,512 | 23,337 | 23,230 | 23,144 | 22,808 | 22,763 |
| Sevier County | 19,976 | 19,961 | 19,682 | 19,366 | 19,031 | 19,101 | 18,956 | 18,948 | 18,912 | 18,868 | 18,842 |
| Summit County | 36,969 | 36,208 | 35,449 | 34,908 | 34,686 | 33,705 | 32,666 | 31,763 | 30,929 | 29,987 | 29,736 |
| Tooele County | 58,335 | 56,865 | 54,720 | 52,353 | 50,092 | 48,669 | 47,333 | 45,577 | 43,726 | 41,615 | 40,735 |
| Uintah County | 31,536 | 29,834 | 28,917 | 27,803 | 26,978 | 26,466 | 26,180 | 26,173 | 25,697 | 25,253 | 25,224 |
| Utah County | 545,307 | 529,755 | 512,902 | 482,291 | 454,694 | 434,114 | 409,465 | 397,269 | 387,853 | 371,648 | 368,536 |
| Wasatch County | 21,600 | 20,976 | 20,395 | 19,891 | 18,726 | 17,827 | 17,382 | 16,735 | 16,090 | 15,417 | 15,215 |
| Washington County | 137,473 | 135,678 | 132,298 | 126,720 | 119,119 | 110,294 | 104,274 | 99,432 | 94,624 | 91,256 | 90,354 |
| Wayne County | 2,601 | 2,558 | 2,487 | 2,462 | 2,402 | 2,419 | 2,459 | 2,514 | 2,507 | 2,529 | 2,509 |
| Weber County | 231,834 | 227,193 | 221,044 | 216,165 | 213,667 | 210,642 | 207,497 | 204,548 | 200,883 | 197,426 | 196,533 |
Source: Population Division, U.S. Census Bureau