(Links below lead to Quick Facts for Arizona 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 |
| Arizona | 6,500,180 | 6,353,421 | 6,178,251 | 5,961,239 | 5,750,475 | 5,585,512 | 5,449,195 | 5,303,632 | 5,166,810 | 5,130,632 |
|---|---|---|---|---|---|---|---|---|---|---|
| Apache County | 70,207 | 69,666 | 69,310 | 68,261 | 67,945 | 67,944 | 67,270 | 67,861 | 69,517 | 69,423 |
| Cochise County | 129,006 | 127,931 | 126,708 | 125,498 | 123,120 | 121,085 | 119,687 | 118,535 | 118,013 | 117,755 |
| Coconino County | 128,558 | 127,350 | 125,966 | 124,653 | 123,235 | 121,460 | 120,333 | 117,771 | 116,703 | 116,320 |
| Gila County | 52,166 | 51,937 | 51,435 | 50,894 | 50,836 | 50,899 | 51,226 | 51,168 | 51,359 | 51,335 |
| Graham County | 36,452 | 34,977 | 33,372 | 32,617 | 32,430 | 32,773 | 33,112 | 33,302 | 33,542 | 33,489 |
| Greenlee County | 8,002 | 7,739 | 7,448 | 7,291 | 7,307 | 7,380 | 7,706 | 8,281 | 8,541 | 8,547 |
| La Paz County | 20,086 | 20,091 | 19,958 | 19,906 | 19,630 | 19,475 | 19,331 | 19,534 | 19,644 | 19,715 |
| Maricopa County | 3,954,598 | 3,865,048 | 3,766,461 | 3,636,250 | 3,495,453 | 3,386,847 | 3,296,790 | 3,199,440 | 3,097,500 | 3,072,149 |
| Mohave County | 196,281 | 195,873 | 192,567 | 185,843 | 178,244 | 170,971 | 165,151 | 159,822 | 156,180 | 155,032 |
| Navajo County | 112,757 | 111,079 | 108,939 | 106,966 | 105,018 | 103,217 | 101,364 | 98,551 | 97,873 | 97,470 |
| Pima County | 1,012,018 | 996,593 | 974,121 | 947,533 | 923,327 | 902,773 | 885,797 | 865,660 | 848,549 | 843,746 |
| Pinal County | 327,301 | 300,873 | 268,715 | 237,154 | 220,519 | 208,641 | 197,764 | 188,350 | 181,276 | 179,727 |
| Santa Cruz County | 42,923 | 42,475 | 41,838 | 40,997 | 40,085 | 39,462 | 39,221 | 38,874 | 38,522 | 38,381 |
| Yavapai County | 215,503 | 212,179 | 206,300 | 197,367 | 189,411 | 183,313 | 178,346 | 173,265 | 168,878 | 167,517 |
| Yuma County | 194,322 | 189,610 | 185,113 | 180,009 | 173,915 | 169,272 | 166,097 | 163,218 | 160,713 | 160,026 |
Source: Population Division, U.S. Census Bureau