Sponsored Topics. Marion is a city in Crittenden County, Kentucky, United States. As of the 2000 census, the city population was 3,196. It is the county seat of Crittenden County. It is named for Francis Marion, a Brigadier General from South Carolina in the American Revolutionary War who was portrayed by Mel Gibson in The Patriot as Benjamin Martin. Marion is located at 37°19′57″N 88°4′45″W / 37.3325°N 88.07917°W / 37.3325; -88.07917 (37.332505, -88.079051). According to the United States Census Bureau, the city has a total area of 3.3 square miles (8.5 km²), of which, 3.3 square miles (8.5 km²) of it is land and 0.30% is water.