Atlantic is a city in, and the county seat of, Cass County, Iowa, United States, located along the East Nishnabotna River. The population was 7,112 in the 2010 census.
Atlantic was founded in October 1868 by Franklin H. Whitney, B.F. Allen, John P. Cook, and others. While historians cannot agree how Atlantic got its name, local legend tells that the founding fathers estimated that the town was about halfway between the Pacific Ocean and the Atlantic Ocean, so it led them to flip a coin and, clearly, Atlantic won. The nearby Rock Island Railroad was important in deciding the actual location of the town, and to this day, the old depot sits at the north end of Chestnut Street. Today, the old depot serves as the offices of the Chamber of Commerce.