| Region 7 | |||||||||||||
| Population | |||||||||||||
| Source: Population Estimates Program, Population Division, U.S. Census Bureau | |||||||||||||
| 1996 | 1997 | 1998 | 1999 | 2000 | 2001 | 2002 | 2003 | 2004 | 2005 | 2006 | 2007 | 2008 | |
| Bonneville | 79,362 | 80,021 | 80,699 | 81,536 | 82,522 | 83,807 | 85,180 | 87,007 | 89,653 | 91,856 | 94,630 | 96,545 | 99,135 |
| Butte | 3,103 | 3,094 | 3,041 | 3,012 | 2,899 | 2,856 | 2,890 | 2,873 | 2,838 | 2,808 | 2,781 | 2,771 | 2,751 |
| Clark | 813 | 839 | 889 | 913 | 1,022 | 971 | 997 | 904 | 906 | 943 | 920 | 906 | 910 |
| Custer | 4,357 | 4,246 | 4,091 | 4,089 | 4,342 | 4,292 | 4,185 | 4,090 | 4,114 | 4,077 | 4,180 | 4,166 | 4,254 |
| Fremont | 11,523 | 11,749 | 11,933 | 11,890 | 11,819 | 11,822 | 11,859 | 12,107 | 12,263 | 12,242 | 12,369 | 12,517 | 12,551 |
| Jefferson | 18,964 | 19,124 | 19,534 | 19,949 | 19,155 | 19,578 | 19,781 | 20,194 | 20,782 | 21,580 | 22,350 | 22,851 | 23,860 |
| Lemhi | 8,056 | 8,064 | 8,041 | 7,978 | 7,806 | 7,606 | 7,649 | 7,731 | 7,820 | 7,909 | 7,930 | 7,717 | 7,808 |
| Madison | 24,547 | 24,875 | 25,125 | 24,806 | 27,467 | 27,327 | 27,686 | 29,878 | 30,782 | 30,975 | 31,393 | 36,647 | 37,456 |
| Teton | 5,117 | 5,288 | 5,490 | 5,708 | 5,999 | 6,419 | 6,859 | 7,058 | 7,253 | 7,467 | 7,838 | 8,349 | 8,833 |
| Total | 155,842 | 157,300 | 158,843 | 159,881 | 163,031 | 164,678 | 167,086 | 171,842 | 176,411 | 179,857 | 184,391 | 192,469 | 197,558 |