Magnolia is a city in Columbia County, Arkansas, United States. According to 2006 Census Bureau estimates, the population of the city is 10,478. The city is the county seat of Columbia County. Population: 11,766 as of June 2007 according to http:www.magnolia-ar.com Magnolia apartments for rent comparison page shows most up to date rent information on Magnolia apartments and houses. Rent information is obtained from multiple rental sources but we cannot guarantee their accuracy.