by Kristen Carney
Updated: February 9, 2026
The richest county in Idaho is Blaine County with an average household income of $135,359 as of 2024 and 24,951 people as of 2024 according to the most current Census data available (citation).
| Rank | County | Population | Average Income | Median Income |
|---|---|---|---|---|
| 1 | Blaine County | 24,951 | $135,359 | $92,566 |
| 2 | Teton County | 12,425 | $130,295 | $99,805 |
| 3 | Ada County | 518,935 | $124,631 | $91,502 |
| 4 | Valley County | 12,389 | $109,882 | $76,078 |
| 5 | Kootenai County | 181,996 | $103,508 | $81,861 |
| 6 | Bonneville County | 129,523 | $102,874 | $79,068 |
| 7 | Jefferson County | 33,154 | $99,354 | $86,679 |
| 8 | Bonner County | 51,049 | $98,751 | $66,979 |
| 9 | Bingham County | 49,664 | $96,279 | $77,878 |
| 10 | Franklin County | 15,056 | $94,804 | $71,950 |
| 11 | Canyon County | 250,790 | $93,734 | $76,488 |
| 12 | Fremont County | 13,943 | $93,018 | $72,683 |
| 13 | Cassia County | 25,483 | $92,485 | $70,830 |
| 14 | Nez Perce County | 42,697 | $91,379 | $72,599 |
| 15 | Madison County | 54,618 | $90,919 | $60,160 |
| 16 | Twin Falls County | 93,734 | $90,415 | $67,409 |
| 17 | Adams County | 4,744 | $90,162 | $61,808 |
| 18 | Jerome County | 25,173 | $89,909 | $71,724 |
| 19 | Boise County | 8,273 | $88,780 | $78,774 |
| 20 | Latah County | 41,049 | $88,649 | $65,424 |
We usually suggest using median income data – either instead of or in addition to – average income data as a true indicator of wealth. If you haven’t thought about median versus average since your last standardized test, you aren’t alone. Here’s what they are:

Now let’s say you had the following simplified set of income data.
Household 1: $30,000
Household 2: $50,000
Household 3: $1,000,000
The average income for this set is $360,000. The outlier data point ($1,000,000) skews the average WAY up. Conversely, the average income would be skewed WAY down if someone had an income of $500. The median income for the same data set is $50,000. Outlier data doesn’t skew the median.
So most business owners should use the median income as a true indicator of wealth, because it provides a more accurate representation of a typical income, especially in areas with significant income disparity.
If your target market is high-income households, the average income may be more relevant. This is because the average income can highlight the presence of a higher concentration of wealthy individuals, which is beneficial for luxury goods and services marketing. We’re using average income on this page because using the Census’s highest reported median value of $250,001 could result in multiple ties for the richest geography.
The Census' American Community Survey uses $250,000+ as a jam value for median income estimates to protect privacy, ensure data consistency, and simplify reporting. A "jam value" in survey data refers to a placeholder or default value used when actual data points are unavailable, incomplete, or exceed certain thresholds. We represent this jam value as $250,001 to make it easy for you to sort.
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United States Census Bureau. Annual Estimates of the Resident Population: April 1, 2020 to July 1, 2024. U.S. Census Bureau, Population Division. Web. May 2025. http://www.census.gov/.
United States Census Bureau. B01001 SEX BY AGE, 2024 American Community Survey 5-Year Estimates. U.S. Census Bureau, American Community Survey Office. Web. 29 January 2026. http://www.census.gov/.
United States Census Bureau. B19013 Median Household Income, 2024 American Community Survey 5-Year Estimates. U.S. Census Bureau, American Community Survey Office. Web. 29 January 2026. http://www.census.gov/.
United States Census Bureau. “DP03 SELECTED ECONOMIC CHARACTERISTICS.” 2024 American Community Survey 5-Year Estimates. U.S. Census Bureau, American Community Survey Office. Web. 29 January 2026. http://www.census.gov/.
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