Many other counties would have been considered bellwether counties, but the outcome of the 2020 presidential election eliminated many of them from this list. Here is a short list of 2020 bellwether counties who lost the effectiveness of prediction:
Allamakee County, Iowa
Baldwin County, Georgia
Butte County, California
Caddo Parish, Louisiana
Calhoun County, South Carolina
Chickasaw County, Mississippi
Colleton County, South Carolina
Columbia County, Wisconsin
Cayuga County, New York
Delaware County, Indiana
Essex County, Virginia
Hill County, Montana
Houston County, Minnesota
Jefferson County, Iowa
Jo Daviess County, Illinois
Lincoln County, Wisconsin
Madison County, New York
Manistee County, Michigan
Marshall County, Iowa
Marshall County, South Dakota
Monroe County, Michigan
Orange County, New York
Oswego County, New York
Porter County, Indiana
Racine County, Wisconsin
Ransom County, North Dakota
Sanusky County, Ohio
Sargent County, North Dakota
Seneca County, New York
Sullivan County, New York
Traverse County, Minnesota
Union County, Iowa
Warren County, New York
Washington County, New York
Winnebago County, Wisconsin