- Your Ad Here Chautauqua County is a county located in the U.S. state of New York. As of the 2016 census, the population was 129,504. Its county seat is Mayville. Sponsored Links History Chautauqua County was created by partition of Genesee County in 1808. Its name may be a contraction of a Seneca Indian word meaning "bag tied in the middle". |