Population Characteristics - Median age
(2021)
To resort data: click column headings. To download
data: click here.
| County Name | Median age
Rank | Median age |
| Adams | 1 | 54.5 |
| Custer | 2 | 53.3 |
| Boise | 3 | 53.0 |
| Lemhi | 4 | 52.6 |
| Clearwater | 5 | 51.2 |
| Idaho | 6 | 49.9 |
| Valley | 7 | 49.4 |
| Bonner | 8 | 48.3 |
| Lewis | 9 | 47.2 |
| Camas | 10 | 46.8 |
| Washington | 11 | 45.7 |
| Benewah | 12 | 45.6 |
| Butte | 13 | 45.3 |
| Shoshone | 14 | 45.3 |
| Blaine | 15 | 44.9 |
| Boundary | 16 | 44.3 |
| Gem | 17 | 43.8 |
| Nez Perce | 18 | 41.2 |
| Oneida | 19 | 40.7 |
| Kootenai | 20 | 40.6 |
| Teton | 21 | 40.2 |
| Clark | 22 | 39.8 |
| Bear Lake | 23 | 39.5 |
| Fremont | 24 | 39.5 |
| Payette | 25 | 39.3 |
| Owyhee | 26 | 39.0 |
| Ada | 27 | 38.4 |
| Caribou | 28 | 37.9 |
| Gooding | 29 | 37.9 |
| Lincoln | 30 | 36.7 |
| Twin Falls | 31 | 36.0 |
| Bannock | 32 | 35.2 |
| Minidoka | 33 | 35.0 |
| Canyon | 34 | 34.7 |
| Bingham | 35 | 34.6 |
| Power | 36 | 34.5 |
| Jerome | 37 | 34.2 |
| Franklin | 38 | 34.2 |
| Elmore | 39 | 33.5 |
| Bonneville | 40 | 33.3 |
| Cassia | 41 | 32.8 |
| Jefferson | 42 | 32.6 |
| Latah | 43 | 31.1 |
| Madison | 44 | 23.7 |
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