Glossary
Bellwether
A place or group whose election results have historically matched the national outcome and are watched as an early indicator.
Also called: bellwether state, bellwether county
A bellwether is a state, county or demographic group whose voting pattern has historically predicted the national result. The word comes from the practice of putting a bell on the lead sheep, or wether, of a flock.
Examples include Ohio, which voted for the winner in every presidential election from 1964 through 2016 before missing in 2020, and Missouri, which was long a bellwether before drifting right. Counties such as Vigo County, Indiana, once held notable records. Analysts study them because they offer clues about trends, and journalists often examine bellwether counties on election night.
Statisticians caution that most bellwether records are coincidences, since only a few presidential elections are available and demographics keep changing, so past performance does not guarantee future predictions. Their usefulness is as a source of information about particular voter groups rather than a prediction. They differ from swing states, which are defined by competitiveness rather than by accuracy. Analysts also look at a generic ballot or an exit poll for more systematic information.
Last reviewed November 8, 2026