(Links below lead to Quick Facts for California 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 |
| California | 36,756,666 | 36,377,534 | 36,121,296 | 35,885,415 | 35,629,666 | 35,307,398 | 34,916,495 | 34,507,030 | 33,998,767 | 33,871,648 |
|---|---|---|---|---|---|---|---|---|---|---|
| Alameda County | 1,474,368 | 1,453,646 | 1,443,492 | 1,439,743 | 1,444,362 | 1,452,923 | 1,461,880 | 1,469,656 | 1,450,396 | 1,443,741 |
| Alpine County | 1,061 | 1,140 | 1,160 | 1,125 | 1,185 | 1,174 | 1,197 | 1,176 | 1,205 | 1,208 |
| Amador County | 38,238 | 38,614 | 38,176 | 37,795 | 37,214 | 36,856 | 36,499 | 35,696 | 35,175 | 35,100 |
| Butte County | 220,337 | 218,185 | 217,131 | 214,873 | 213,193 | 211,584 | 209,299 | 206,366 | 203,907 | 203,171 |
| Calaveras County | 46,843 | 46,748 | 46,524 | 45,710 | 44,867 | 44,013 | 42,587 | 41,435 | 40,698 | 40,554 |
| Colusa County | 21,204 | 21,148 | 20,977 | 20,595 | 20,254 | 19,600 | 19,282 | 19,042 | 18,816 | 18,804 |
| Contra Costa County | 1,029,703 | 1,014,687 | 1,005,699 | 1,002,051 | 994,844 | 989,171 | 981,420 | 972,016 | 953,304 | 948,816 |
| Del Norte County | 29,100 | 28,933 | 28,577 | 28,504 | 28,107 | 27,736 | 27,492 | 27,344 | 27,471 | 27,507 |
| El Dorado County | 176,075 | 175,199 | 174,871 | 173,410 | 170,409 | 167,371 | 164,619 | 160,814 | 157,128 | 156,299 |
| Fresno County | 909,153 | 894,748 | 882,171 | 870,620 | 859,729 | 846,210 | 829,729 | 813,476 | 802,123 | 799,407 |
| Glenn County | 28,237 | 27,959 | 27,763 | 27,503 | 27,228 | 27,098 | 26,721 | 26,495 | 26,449 | 26,453 |
| Humboldt County | 129,000 | 128,614 | 129,077 | 128,963 | 128,703 | 128,224 | 127,784 | 127,003 | 126,400 | 126,518 |
| Imperial County | 163,972 | 160,830 | 156,999 | 153,285 | 150,078 | 147,359 | 144,629 | 143,177 | 142,411 | 142,361 |
| Inyo County | 17,136 | 17,394 | 17,534 | 17,717 | 17,961 | 18,120 | 18,081 | 17,942 | 17,916 | 17,945 |
| Kern County | 800,458 | 787,179 | 770,221 | 748,766 | 727,068 | 707,673 | 689,617 | 674,235 | 663,510 | 661,645 |
| Kings County | 149,518 | 148,232 | 145,723 | 143,507 | 142,390 | 138,879 | 134,781 | 132,502 | 129,776 | 129,461 |
| Lake County | 64,866 | 64,498 | 64,662 | 64,132 | 63,376 | 62,679 | 61,657 | 60,308 | 58,547 | 58,309 |
| Lassen County | 34,574 | 34,980 | 34,083 | 34,061 | 34,119 | 33,709 | 33,308 | 33,505 | 33,748 | 33,828 |
| Los Angeles County | 9,862,049 | 9,807,870 | 9,826,493 | 9,846,010 | 9,841,217 | 9,801,378 | 9,733,679 | 9,643,067 | 9,544,112 | 9,519,338 |
| Madera County | 148,333 | 145,654 | 143,331 | 140,049 | 136,783 | 132,200 | 127,949 | 125,474 | 123,572 | 123,109 |
| Marin County | 248,794 | 246,932 | 245,228 | 244,520 | 244,036 | 245,281 | 246,483 | 248,032 | 247,597 | 247,289 |
| Mariposa County | 17,976 | 17,994 | 17,925 | 17,713 | 17,656 | 17,582 | 17,200 | 17,106 | 17,144 | 17,130 |
| Mendocino County | 86,221 | 85,960 | 86,370 | 86,986 | 87,214 | 87,481 | 86,940 | 86,620 | 86,385 | 86,265 |
| Merced County | 246,117 | 244,218 | 241,254 | 238,034 | 233,471 | 228,763 | 223,296 | 217,457 | 211,552 | 210,554 |
| Modoc County | 9,184 | 9,169 | 9,312 | 9,279 | 9,375 | 9,334 | 9,252 | 9,298 | 9,416 | 9,449 |
| Mono County | 12,774 | 12,758 | 12,974 | 12,781 | 12,804 | 12,924 | 13,069 | 13,002 | 12,896 | 12,853 |
| Monterey County | 408,238 | 404,646 | 403,922 | 406,887 | 410,223 | 411,385 | 409,810 | 407,350 | 403,095 | 401,762 |
| Napa County | 133,433 | 131,781 | 130,866 | 130,056 | 130,149 | 129,904 | 128,639 | 126,753 | 124,538 | 124,279 |
| Nevada County | 97,118 | 96,853 | 96,714 | 96,573 | 95,987 | 95,203 | 94,416 | 93,595 | 92,505 | 92,033 |
| Orange County | 3,010,759 | 2,976,742 | 2,970,485 | 2,969,335 | 2,965,561 | 2,947,155 | 2,921,827 | 2,893,531 | 2,856,918 | 2,846,289 |
| Placer County | 341,945 | 332,121 | 323,758 | 314,775 | 304,478 | 291,921 | 277,833 | 264,212 | 251,255 | 248,399 |
| Plumas County | 20,275 | 20,586 | 20,747 | 20,972 | 20,974 | 20,936 | 20,864 | 20,827 | 20,765 | 20,824 |
| Riverside County | 2,100,516 | 2,064,365 | 2,000,816 | 1,922,386 | 1,849,378 | 1,766,393 | 1,684,378 | 1,615,534 | 1,559,277 | 1,545,387 |
| Sacramento County | 1,394,154 | 1,380,232 | 1,367,737 | 1,357,916 | 1,346,677 | 1,326,638 | 1,300,112 | 1,265,948 | 1,230,247 | 1,223,499 |
| San Benito County | 54,699 | 54,397 | 54,448 | 54,927 | 55,082 | 55,369 | 55,205 | 54,741 | 53,823 | 53,234 |
| San Bernardino County | 2,015,355 | 2,002,208 | 1,981,696 | 1,949,205 | 1,903,703 | 1,850,737 | 1,802,453 | 1,762,539 | 1,718,675 | 1,709,434 |
| San Diego County | 3,001,072 | 2,959,734 | 2,937,023 | 2,931,689 | 2,930,053 | 2,927,311 | 2,905,609 | 2,869,630 | 2,825,395 | 2,813,833 |
| San Francisco County | 808,976 | 799,185 | 786,367 | 776,614 | 772,417 | 774,359 | 778,773 | 784,385 | 777,532 | 776,733 |
| San Joaquin County | 672,388 | 667,886 | 662,395 | 655,866 | 642,049 | 626,014 | 608,858 | 591,263 | 568,023 | 563,598 |
| San Luis Obispo County | 265,297 | 261,766 | 259,650 | 257,779 | 256,250 | 254,353 | 252,985 | 251,525 | 247,876 | 246,681 |
| San Mateo County | 712,690 | 701,675 | 696,825 | 694,675 | 693,961 | 695,868 | 700,005 | 707,190 | 708,442 | 707,161 |
| Santa Barbara County | 405,396 | 402,092 | 400,393 | 401,576 | 402,128 | 403,083 | 402,529 | 401,690 | 399,826 | 399,347 |
| Santa Clara County | 1,764,499 | 1,731,958 | 1,707,810 | 1,687,956 | 1,673,298 | 1,671,012 | 1,675,204 | 1,691,612 | 1,686,154 | 1,682,585 |
| Santa Cruz County | 253,137 | 250,655 | 249,643 | 249,603 | 250,905 | 251,899 | 253,917 | 255,754 | 255,850 | 255,602 |
| Shasta County | 180,214 | 179,068 | 178,252 | 177,541 | 176,466 | 174,406 | 171,129 | 166,962 | 163,782 | 163,256 |
| Sierra County | 3,263 | 3,312 | 3,381 | 3,338 | 3,400 | 3,487 | 3,468 | 3,509 | 3,569 | 3,555 |
| Siskiyou County | 44,542 | 44,195 | 44,246 | 44,421 | 44,241 | 44,172 | 43,920 | 43,901 | 44,233 | 44,301 |
| Solano County | 407,515 | 407,042 | 407,085 | 407,269 | 408,850 | 408,734 | 408,039 | 403,955 | 396,971 | 394,542 |
| Sonoma County | 466,741 | 462,290 | 460,947 | 462,299 | 463,915 | 464,222 | 463,902 | 464,608 | 460,425 | 458,614 |
| Stanislaus County | 510,694 | 509,068 | 505,205 | 499,822 | 492,442 | 487,104 | 477,538 | 463,940 | 449,708 | 446,997 |
| Sutter County | 92,207 | 91,552 | 89,800 | 87,659 | 85,645 | 84,062 | 81,763 | 79,931 | 79,127 | 78,930 |
| Tehama County | 61,550 | 60,956 | 60,408 | 59,635 | 58,818 | 57,952 | 57,007 | 56,476 | 56,135 | 56,039 |
| Trinity County | 14,317 | 14,141 | 13,927 | 13,643 | 13,337 | 13,342 | 13,162 | 12,919 | 13,007 | 13,022 |
| Tulare County | 426,276 | 419,172 | 412,048 | 405,142 | 396,120 | 387,214 | 378,824 | 372,869 | 368,695 | 368,021 |
| Tuolumne County | 55,644 | 55,727 | 56,104 | 56,255 | 56,172 | 56,198 | 55,671 | 55,158 | 54,651 | 54,501 |
| Ventura County | 797,740 | 792,456 | 791,247 | 788,565 | 789,670 | 785,220 | 777,421 | 765,710 | 756,414 | 753,197 |
| Yolo County | 197,658 | 194,634 | 189,623 | 186,285 | 185,305 | 182,972 | 180,396 | 175,434 | 169,870 | 168,660 |
| Yuba County | 73,067 | 71,750 | 70,001 | 67,019 | 64,369 | 63,451 | 62,388 | 61,335 | 60,330 | 60,219 |
Source: Population Division, U.S. Census Bureau