Jefferson County may refer to the following counties in the United States:
Jefferson County, Alabama Jefferson County, Arkansas Jefferson County, Colorado Jefferson County, Jefferson Territory Jefferson County, Florida Jefferson County, Georgia Jefferson County, Idaho Jefferson County, Illinois Jefferson County, Indiana Jefferson County, Iowa Jefferson County, Kansas Jefferson County, Kentucky Jefferson County, Mississippi Jefferson County, Missouri Jefferson County, Montana Jefferson County, Nebraska Jefferson County, New York Jefferson County, Ohio Jefferson County, Oklahoma Jefferson County, Oregon Jefferson County, Pennsylvania Jefferson County, Tennessee Jefferson County, Texas Jefferson County, Virginia, has existed twice; the two counties continue in existence as Jefferson County, Kentucky and Jefferson County, West Virginia Jefferson County, Washington Jefferson County, West Virginia Jefferson County, Wisconsin
See also Jefferson County (The Waltons), a fictional county in Virginia Jefferson Parish, Louisiana Jefferson Davis Parish, Louisiana Jefferson Davis County, Mississippi Jeff Davis County (disambiguation)