On June 19 Johnston created a solid defensive line at Kennesaw Mountain that Sherman failed to avoid after a Confederate counterattack on June 22 at Kolb’s Farm prevented him from doing so. This attack did not result in significant Union losses, but it made Sherman choose between sending his army farther south to still avoid the Confederate army or taking on the Confederates head on. Sherman ordered his men to attack arguing that the Confederates’ attack at Kolb’s Farm had weakened them. Sherman's force of 100,000 men and 35,000 horses outnumbered Johnston's 50,000.
At 9:00am on June 27, Sherman’s army attacked the Confederate troops and continued along the bottom of Kennesaw Mountain, but the Confederates were able to fight them off. At the same time, the rough land and Confederate forces hindered a Union attack at Pigeon Hill. At Cheatham Hill, the most intense fighting took place in a section of the Confederate line called “Dead Angle” by the Confederates. The Union soldiers tried to break through the Confederate trenches but failed due to the terrain and a strong defense from the Confederates. Despite Sherman's superior numbers the battle was a Confederate victory. There were an estimated 5,350 casualties, including Union Generals Charles Harker and Daniel McCook, who were killed. The battle was one the bloodiest one-day battles in the Atlanta Campaign. While Sherman lost, it did not stop him from pushing toward Atlanta, and he still strategically had the upper hand, the men, and the will to keep pursuing Johnston’s men.
The park was created in 1935 to commemorate the battle and now consists of 2,965 acres. It contains the Kennesaw Mountain Battlefield, Kennesaw Mountain Road, and the Cheatham Hill Battlefield grounds. The battlefield grounds preserve the historic battlefield and include reconstructed fortifications and cannon emplacements. The site also includes the Kolb Farm House which has been restored. The number of visitors here every year have rose from 4,700 in 1939 to 1.4 million in 2004. Contributing to the high number of visitors is the fact that the park is the biggest rural area close to the city of Atlanta. The site also has a range of activities including: 18 miles of hiking trails, a visitor center that plays a 35 minute video on the Atlanta Campaign and the battle, a Civil War museum, and the visitor center also has a bookstore. The site celebrated its 150th anniversary in June of 2014.