Jefferson County er navnet på 26 counties og en parish i USA:
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 Parish, Louisiana 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, Washington Jefferson County, West Virginia Jefferson County, Wisconsin Andet: Jefferson County (The Waltons), en fiktiv county i Virginia
Se også Jefferson Davis Parish, Louisiana Jefferson Davis County, Mississippi Jeff Davis County (flertydig)