Montour County is a county in the Commonwealth of Pennsylvania. As of the 2020 census, the population was 18,136. Its county seat is Danville. The county is named for Andrew Montour, a prominent Métis interpreter who served with George Washington during the French and Indian War. It encompasses 132 sq mi, making it the smallest county by land area in the state. The county is part of the Central Pennsylvania region of the state.