From Ohio History Central
Camp Jackson was located near Columbus, Ohio. Governor William Dennison ordered the establishment of the post as a training camp for Ohio volunteers during the American Civil War. In April 1861, following President Abraham Lincoln's call for seventy-five thousand volunteers to end the South's rebellion, Governor Dennison encouraged Ohio communities to form and send militia units to the state capital at Columbus. Camp Jackson served as the training ground for these units. Military authorities also reorganized these individual companies into large military units.
While the state militia system had deteriorated throughout the first half of the nineteenth century, numerous communities had maintained units. These units existed primarily to march in parades and to provide young men with something to do in their spare time. Among these units was the Lancaster Guards. This company quickly answered the governor's call and was the first militia unit to arrive in Columbus at Camp Jackson in 1861. It served as part of the first two Ohio infantry regiments organized for the war. Governor Dennison dispatched these regiments to Washington, DC, to protect the nation's capital, on April 19, 1861. This was just four days after President Lincoln's call for volunteers. Ohio's governor sent other units to Camp Dennison, near Cincinnati, to help defend Ohio's southern border from a Confederate invasion. The soldiers at Camp Jackson usually remained at the camp for only a short time. After receiving a little training, military officials would send the men off to war. Camp Chase, organized in Columbus in 1861, eventually replaced Camp Jackson.