| Region 4 | ||||||||||||
| Population Age by County, 2000 | ||||||||||||
| Source: U.S. Census Bureau, Census 2000 | ||||||||||||
| Age in Years | 0-9 | 10-14 | 15-19 | 20-24 | 25-34 | 35-44 | 45-54 | 55-59 | 60-64 | 65-74 | 75-84 | 85+ |
| Ada | 45917 | 22551 | 22237 | 22254 | 47810 | 50119 | 41059 | 12705 | 8953 | 13813 | 10020 | 3468 |
| Boise | 882 | 544 | 477 | 206 | 631 | 1177 | 1231 | 464 | 326 | 466 | 218 | 48 |
| Elmore | 4712 | 2167 | 2115 | 3211 | 5445 | 5035 | 2643 | 921 | 802 | 1203 | 672 | 204 |
| Valley | 785 | 602 | 556 | 205 | 645 | 1260 | 1426 | 549 | 489 | 693 | 337 | 104 |