Marion is a city in, and the county seat of, Marion County, Kansas, United States. It was named in honor of Francis Marion, a Brigadier General of the American Revolutionary War, known as the "Swamp Fox". At the 2010 census, the city population was 1,927.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.In 1802, Spain returned most of the land to France. In 1803, most of the land for modern day Kansas was acquired by the United States from France as part of the 828,000 square mile Louisiana Purchase for 2.83 cents per acre.