list of counties in Idaho

There are 44 counties in the U.S. state of Idaho.

The Idaho Territory was organized in March 1863, and Owyhee County was the first county in the territory to be organized, in December of that year. Oneida County was organized in January 1864, while Missoula County was adopted the same month, before becoming part of the new Montana Territory in May. Shoshone, Nez Perce, Idaho and Boise Counties were recognized in February 1864; Alturas County was organized the same month. In December 1864, Kootenai and Ada Counties were created; Lah-Toh County was also created at this time but was abolished in 1867.