United States Historical Geography

Portal:United States of America

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. A county history is the best source of information about a county's origin. Other sources that can help you determine the origin of a county are:


 * 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. (Family History Library book 973 E2ka 1983.)


 * The Handy Book for Genealogists. Eighth Edition. Logan, Utah: Everton Publishers, 1991. (Family History Library book 973 D27e 1991.)

Online interactive state maps—highlighting county creations and boundary changes year-by-year—are available free at FamilyHistory101.com (for 36 states), along with census maps, road maps, and maps from antiquity.

Other sources about boundary changes are found in the Place Search of the Family History Library Catalog under UNITED STATES - HISTORICAL GEOGRAPHY. The historical atlases described in the “Maps” section of this outline contain maps depicting county formations, migration and settlement patterns, military actions, ethnic distribution, religious trends, and population trends.