Which Counties in Idaho are Reporting the Most Cases of Breast Cancer

Idahoans, specifically women, are among the least likely to get screened for breast cancer in the United States. While the recommended age for screening is once every two years for women between the ages of 47 and 74, only a small percentage follow that suggestion.

Inside Idaho, the cancer rates vary by county, with some locations reporting low breast cancer diagnoses and many counties reporting levels above the national average.

How is Breast Cancer Affecting Your Local Community in Idaho

When we looked at the data to see which counties in Idaho are being hit the hardest by breast cancer, we found that the rates vary each year. There isn’t one county that is the worst every year. Instead, the fluctuation of counties with the most breast cancer reports shows us that breast cancer is everywhere.

Recent reports show that the percentage to population of positive breast cancer diagnoses in each county are highest in Lewis, Franklin, Owyhee, Ada, and Washington Counties. Kootenai, Canyon, Twin Falls, Bannock, and other counties reported more breast cancer cases than the five listed above (with the exception of Ada County); the percentage rate is higher in the lower population counties.

Previous year reports placed Clearwater, Washington, Shoshone, Adams, and Lemhi in the top five.

READ ALSO: Is Breast Cancer Screening Coverage Required in Idaho

Overall cancer rates in Idaho are highest in Elmore, Lewis, Shoshone, Owyhee, Washington, and Butte Counties based on data released in April of 2025. The gallery below lists each county ranked by breast cancer cases.