thumb|right|An 1891 lithograph of the Battle of Kennesaw Mountain by Kurz & Allison During the American Civil War, some Confederate troops were trained at a camp in Big Shanty (now Kennesaw), where the Andrews Raid occurred, starting the Great Locomotive Chase. There were battles of New Hope Church May 25, 1864, Pickett's Mill May 27, and Dallas May 28. These were followed by the prolonged series of battles through most of June 1864 until very early July: the Battle of Marietta and the Battle of Noonday Creek. The Battle of Allatoona Pass on October 5, 1864, occurred as Sherman was starting his march through Georgia. Union forces burnt most houses and confiscated or burnt crops. The Battle of Kennesaw Mountain on June 27, 1864, was the site of the only major Confederate victory in General William T. Sherman's invasion of Georgia. Despite the victory, Union forces outflanked the Confederates. In 1915, Leo Frank, the Jewish supervisor of an Atlanta pencil factory who was convicted of murdering one of his workers, thirteen-year-old Mary Phagan, was kidnapped from his jail cell and brought to Frey's Gin, east of Marietta, where he was lynched. thumb|Cotton workers in Mableton, around 1900 Cotton farming in the area peaked from the 1890s through the 1920s. Low prices during the Great Depression resulted in the cessation of cotton farming throughout Cobb County. The price of cotton went from 16¢ per pound (35¢/kg) in 1920 to 9½¢ (21¢/kg) in 1930. This resulted in a cotton bust for the county, which had stopped growing the product but was milling it. This bust was followed by the Great Depression. To help combat the bust, the state started work on a road in 1922 that would later become U.S. 41, later replaced by Cobb Parkway in the late 1940s and early 1950s.
thumb|right|An 1891 lithograph of the Battle of Kennesaw Mountain by Kurz & Allison During the American Civil War, some Confederate troops were trained at a camp in Big Shanty (now Kennesaw), where the Andrews Raid occurred, starting the Great Locomotive Chase There were battles of New Hope Church May 25, 1864, Pickett's Mill May 27, and Dallas May 28. These were followed by the prolonged series of battles through most of June 1864 until very early July: the Battle of Marietta and the Battle of Noonday Creek. The Battle of Allatoona Pass on October 5, 1864, occurred as Sherman was starting his march through Georgia. Union forces burnt most houses and confiscated or burnt crops. The Battle of Kennesaw Mountain on June 27, 1864, was the site of the only major Confederate victory in General William T. Sherman's invasion of Georgia. Despite the victory, Union forces outflanked the Confederates In 1915 Leo Frank, the Jewish supervisor of an Atlanta pencil factory who was convicted of murdering one of his workers, thirteen-year-old Mary Phagan, was kidnapped from his jail cell and brought to Frey's Gin, east of Marietta, where he was lynched. thumb|Cotton workers in Mableton, around 1900 Cotton farming in the area peaked from the 1890s through the 1920s. Low prices during the Great Depression resulted in the cessation of cotton farming throughout Cobb County. The price of cotton went from 16¢ per pound (35¢/kg) in 1920 to 9½¢ (21¢/kg) in 1930. This resulted in a cotton bust for the county, which had stopped growing the product but was milling it. This bust was followed by the Great Depression. To help combat the bust, the state started work on a road in 1922 that would later become U.S. 41, later replaced by Cobb Parkway in the late 1940s and early 1950s.