Idaho Historical Geography

Because counties were often divided and their names and boundaries changed, you may need to determine previous boundaries and jurisdictions to locate your ancestors' records.

The Idaho Genealogical Society has a list of Idaho counties online, with their dates of origin.

Other sources that can help you determine the origin of a county are:


 * A county history often contains good information about a county's origin.
 * Kane, Joseph Nathan. The American Counties: Origins of Names, Dates of Creation and Organization, Area, Population, Historical Data, and Published Sources. Fourth Edition. Metuchen, New Jersey: Scarecrow Press, 1983. (FS Library book 1983.)
 * The Handy Book for Genealogists. Eleventh Edition. Logan, Utah: Everton Publishers, c2006. (FS Library book .)