Potwin is a city in Butler County, Kansas, United States. It is named after the town site land owner Charles Potwin. As of the 2020 census, the population of the city was 421. For many millennia, the Great Plains of North America was inhabited by nomadic Native Americans. From the 16th century to 18th century, the Kingdom of France claimed ownership of large parts of North America. In 1762, after the French and Indian War, France secretly ceded New France to Spain, per the Treaty of Fontainebleau.