Marion is a city in and the county seat of Perry County, Alabama, United States. As of the 2010 census, the population of the city is 3,686, up …Marion is a city in and the county seat of Perry County, Alabama, United States. As of the 2010 census, the population of the city is 3,686, up 4.8% over 2000. First known as Muckle Ridge, the city was renamed for a hero of the American Revolution, Francis Marion.