Aberdeen is a city in Monroe County in the U.S. state of Mississippi. The population was 6,415 at the 2000 census. It is the county seat of Monroe County. Located on the banks of the Tombigbee River, Aberdeen was one of the busiest Mississippi ports of the nineteenth century. Cotton was heavily traded in town, and for a time Aberdeen was Mississippi's second largest city. Today Aberdeen retains many historic structures from this period, with over 200 buildings on the National Register of Historic Places. In the spring of each year, Aberdeen hosts pilgrimages to its historic antebellum homes. The most prominent of these antebellum homes is The Magnolias, which was built in 1850. Located just outside the city, Aberdeen Lock and Dam forms Aberdeen Lake, a popular recreational area. Aberdeen Lock and Dam is part of the Tennessee-Tombigbee waterway system.