This is a categorized list of Idaho county namesakes.
Below are categorized the names of counties by their sources. Each county is counted only once in the main entries, unless where the origin is not certain. Those listed under "plus" appeared in previous categories, e.g. "Fremont" is counted under "Explorers", but listed under "U.S. Congressmen and Secretaries of State" for completeness.
For the original etymologies, see List of Idaho county name etymologies.
Of Idaho's 44 counties:
Rivers, lakes, and waterfalls:
Eight counties: Bear Lake, Boise, Cassia, Clearwater, Latah, Oneida, Payette, and Twin Falls.
Buttes, canyons, mountain ranges, and valleys:
Five counties: Butte, Canyon, Caribou, Teton, and Valley.
Presidents of the United States:
Five counties: Adams, Jefferson, Lincoln, Madison, and Washington.
Native American tribes:
Four counties: Bannock, Kootenai, Nez Perce, and Shoshone.
Pioneers and state congressmen:
Four counties: Ada, Bonner, Clark, and Jerome.
Explorers:
Three counties: Bonneville, Fremont, and Lewis.
Mining:
Two counties: Custer and Elmore.
U.S. Congressmen and Secretaries of State:
Two counties: Bingham and Blaine
Plus: Fremont, Jefferson, Lincoln, and Madison.
Native American words:
One county: Minidoka.
Cities in Idaho:
One county: Franklin.
Governors of Idaho:
One county: Gooding.
Latter-day Saint locations:
One county: Lemhi.
Native American leaders:
One county: Benewah.
Plants:
One county: Camas.
Political location:
One county: Boundary.
Power Plants:
One county: Power.
State nicknames:
One county: Gem.
Steamships
One county: Idaho
U.S. states excluding Idaho:
One county: Owyhee.
