(Links below lead to Quick Facts for Oregon 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 |
| Oregon | 3,825,657 | 3,782,991 | 3,732,957 | 3,677,545 | 3,617,869 | 3,573,505 | 3,550,180 | 3,517,111 | 3,470,382 | 3,430,891 | 3,421,399 |
|---|---|---|---|---|---|---|---|---|---|---|---|
| Baker County | 16,082 | 16,051 | 16,010 | 15,989 | 16,001 | 16,202 | 16,270 | 16,351 | 16,609 | 16,717 | 16,741 |
| Benton County | 82,605 | 81,775 | 81,583 | 80,145 | 79,427 | 78,949 | 79,414 | 79,622 | 78,175 | 78,197 | 78,153 |
| Clackamas County | 386,143 | 381,229 | 375,610 | 370,897 | 365,411 | 360,709 | 355,730 | 351,647 | 344,842 | 339,546 | 338,391 |
| Clatsop County | 37,243 | 37,093 | 37,088 | 36,763 | 36,447 | 36,060 | 35,778 | 35,606 | 35,542 | 35,571 | 35,630 |
| Columbia County | 49,592 | 49,339 | 48,914 | 48,227 | 46,987 | 46,226 | 45,664 | 45,146 | 44,228 | 43,657 | 43,560 |
| Coos County | 62,795 | 62,970 | 63,149 | 63,602 | 63,636 | 63,063 | 62,525 | 62,234 | 62,161 | 62,668 | 62,779 |
| Crook County | 22,566 | 22,892 | 22,760 | 22,476 | 21,670 | 21,165 | 20,400 | 20,064 | 19,876 | 19,318 | 19,182 |
| Curry County | 21,148 | 21,235 | 21,507 | 21,809 | 22,064 | 21,924 | 21,490 | 21,373 | 21,097 | 21,104 | 21,137 |
| Deschutes County | 158,629 | 157,730 | 153,405 | 148,670 | 140,962 | 134,080 | 129,322 | 125,468 | 120,667 | 116,618 | 115,367 |
| Douglas County | 103,205 | 103,529 | 103,688 | 103,685 | 102,817 | 102,010 | 101,307 | 100,579 | 100,069 | 100,423 | 100,399 |
| Gilliam County | 1,645 | 1,698 | 1,655 | 1,690 | 1,739 | 1,762 | 1,749 | 1,827 | 1,875 | 1,908 | 1,915 |
| Grant County | 6,795 | 6,864 | 6,868 | 7,020 | 7,092 | 7,183 | 7,295 | 7,327 | 7,445 | 7,903 | 7,935 |
| Harney County | 6,756 | 6,761 | 6,770 | 6,798 | 6,801 | 6,975 | 7,096 | 7,231 | 7,382 | 7,629 | 7,609 |
| Hood River County | 21,883 | 21,469 | 21,169 | 21,111 | 20,946 | 20,783 | 20,582 | 20,597 | 20,396 | 20,472 | 20,411 |
| Jackson County | 201,286 | 200,298 | 198,346 | 196,165 | 194,087 | 191,697 | 189,469 | 186,567 | 183,797 | 181,798 | 181,269 |
| Jefferson County | 19,959 | 20,375 | 20,520 | 19,964 | 19,668 | 19,577 | 19,633 | 19,560 | 19,457 | 19,101 | 19,009 |
| Josephine County | 81,026 | 81,174 | 80,693 | 80,632 | 79,834 | 79,080 | 78,285 | 77,413 | 76,304 | 75,839 | 75,726 |
| Klamath County | 66,247 | 66,543 | 66,562 | 66,095 | 65,402 | 64,753 | 64,549 | 64,097 | 64,110 | 63,893 | 63,775 |
| Lake County | 7,089 | 7,203 | 7,210 | 7,215 | 7,078 | 7,188 | 7,280 | 7,321 | 7,426 | 7,409 | 7,422 |
| Lane County | 351,109 | 348,425 | 344,812 | 339,280 | 335,242 | 331,876 | 330,447 | 327,394 | 324,829 | 323,505 | 322,959 |
| Lincoln County | 46,293 | 46,138 | 45,945 | 45,640 | 45,442 | 44,968 | 44,493 | 44,341 | 43,903 | 44,345 | 44,479 |
| Linn County | 116,584 | 115,369 | 113,094 | 110,923 | 108,244 | 106,894 | 106,095 | 104,645 | 103,594 | 103,015 | 103,069 |
| Malheur County | 30,745 | 30,832 | 30,993 | 30,892 | 30,914 | 30,965 | 31,115 | 31,315 | 31,476 | 31,527 | 31,615 |
| Marion County | 317,981 | 313,677 | 310,155 | 305,869 | 301,463 | 298,779 | 296,530 | 293,537 | 288,744 | 285,564 | 284,834 |
| Morrow County | 11,533 | 11,326 | 11,323 | 11,432 | 11,355 | 11,437 | 11,447 | 11,413 | 11,104 | 11,024 | 10,995 |
| Multnomah County | 726,855 | 712,539 | 697,048 | 682,732 | 673,823 | 671,704 | 678,549 | 676,417 | 669,591 | 661,738 | 660,486 |
| Polk County | 78,122 | 76,884 | 74,910 | 72,813 | 70,019 | 67,720 | 65,933 | 64,765 | 63,800 | 62,658 | 62,380 |
| Sherman County | 1,711 | 1,664 | 1,690 | 1,661 | 1,660 | 1,667 | 1,746 | 1,756 | 1,845 | 1,921 | 1,934 |
| Tillamook County | 24,889 | 24,907 | 25,023 | 24,952 | 24,798 | 24,644 | 24,473 | 24,345 | 24,335 | 24,254 | 24,262 |
| Umatilla County | 73,347 | 72,787 | 72,850 | 72,790 | 72,752 | 72,654 | 72,209 | 71,769 | 70,484 | 70,700 | 70,548 |
| Union County | 25,038 | 25,073 | 25,061 | 24,479 | 24,456 | 24,327 | 24,472 | 24,470 | 24,349 | 24,544 | 24,530 |
| Wallowa County | 6,889 | 6,843 | 6,822 | 6,768 | 6,817 | 6,854 | 6,971 | 7,018 | 7,097 | 7,215 | 7,226 |
| Wasco County | 24,149 | 23,820 | 23,734 | 23,543 | 23,412 | 23,400 | 23,563 | 23,487 | 23,695 | 23,818 | 23,791 |
| Washington County | 537,318 | 527,168 | 518,427 | 510,023 | 497,073 | 485,249 | 478,103 | 471,401 | 462,316 | 448,494 | 445,342 |
| Wheeler County | 1,363 | 1,371 | 1,396 | 1,403 | 1,396 | 1,457 | 1,503 | 1,522 | 1,496 | 1,543 | 1,547 |
| Yamhill County | 99,037 | 97,940 | 96,167 | 93,392 | 90,934 | 89,524 | 88,693 | 87,486 | 86,266 | 85,255 | 84,992 |
Source: Population Division, U.S. Census Bureau