Atlantic was founded in October 1868 by Franklin H. Whitney, B.F. Allen, John P. Cook, Connie F. Beemer, 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 lead 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.
Another story told about Atlantic is the way main street was located. Someone asked Whitney where it should be placed. He marked the center at current day 6th and Chestnut and then plowed two furrows a 100 feet apart all the way up to the railroad, just north of Second Street.
According to the United States Census Bureau, the city has a total area of 8.2 square miles (21.2 km²), of which, 8.1 square miles (21.1 km²) of it is land and 0.04 square miles (0.1 km²) of it (0.37%) is water.
There were 3,126 households out of which 28.5% had children under the age of 18 living with them, 51.0% were married couples living together, 8.8% had a female householder with no husband present, and 37.0% were non-families. 33.7% of all households were made up of individuals and 18.0% had someone living alone who was 65 years of age or older. The average household size was 2.22 and the average family size was 2.81.
In the city the population was spread out with 23.0% under the age of 18, 7.4% from 18 to 24, 24.3% from 25 to 44, 22.3% from 45 to 64, and 23.0% who were 65 years of age or older. The median age was 42 years. For every 100 females there were 89.3 males. For every 100 females age 18 and over, there were 83.5 males.
The median income for a household in the city was $33,370, and the median income for a family was $41,168. Males had a median income of $30,691 versus $20,271 for females. The per capita income for the city was $17,832. About 6.3% of families and 12.1% of the population were below the poverty line, including 17.5% of those under age 18 and 10.6% of those age 65 or over.
Atlantic, Iowa is one of the smallest communities in Iowa to have a daily newspaper - The Atlantic News Telegraph.
Atlantic is also home to three radio stations.
96.5 KSOM which features country music, Paul Harvey, Farm Reports, Local News, Iowa State Sports and Nascar. KSWI 95.7 which features classic rock and Atlantic high school sports. KJAN 1220AM which features an adult contemporary format.