With the American Civil War's outbreak, neither the North nor the South had sufficient military forces to conduct a war. Both the United States of America and the Confederate States of America, at first, relied upon volunteers either to form or to bolster their respective militaries.
With the American Civil War's outbreak, neither the North nor the South had sufficient military forces to conduct a war. Both the United States of America and the Confederate States of America, at first, relied upon volunteers either to form or to bolster their respective militaries. Typically, individual states would recruit and send volunteers to their respective federal governments. Initially, many states relied on militia forces. Historically, every British colony in North America had established a militia. The militia usually consisted of adult, able-bodied men, who would rally to defend the colonies and, following the American Revolution, states during military crises. By the start of the American Civil War, unfortunately for both the Confederate States of America and the United States of America, most state militias were in a decline and unprepared for a major war.
In Ohio, Governor William Dennison hoped to supply the United States government with men and supplies from the Ohio militia. Ohio's militia system was virtually nonexistent by 1861. While militia forces played a vital role in Ohio's history from the American Revolution to the War of 1812, most major military threats to Ohio's security ended with the War of 1812. Following this conflict, the federal government quickly removed most Native Americans further west, and in the decades immediately following the war, no European or other major power attacked the United States. Facing no serious internal or external threats, most states, including Ohio, allowed their militia organizations to weaken. Most militia groups became mere social organizations and did not actively practice or study military maneuvers or tactics.
Dennison quickly discovered that Ohio's militia system could not play an active role in the American Civil War. Following the Battle of Fort Sumter and President Abraham Lincoln’s call for seventy-five thousand volunteers to return the seceded states to the Union in April 1861, Ohio's governor sent Jacob Cox, a state politician, and George McClellan, a former United States Army officer and current businessman, to Ohio's arsenal to assess the availability of weapons and supplies. Cox and McClellan found three or four crates of smoothbore muskets, a number of inoperable six-pound cannons, and some mildewed horse harnesses. Upon learning of the dire condition of the state's military supplies, Dennison still encouraged Ohioans to reestablish militia units to defend the state from Southern attack and to assist the federal government in reuniting the nation.
Ohioans quickly responded to the governor's and the federal government's call for troops. Among Ohio's earliest regiments was the 18th Regiment Ohio Volunteer Infantry. This organization enrolled between April 17, 1861 and April 24, 1861. Companies A, C, and E organized at Ironton, Ohio on April 22, 1861. Company B formed at Marietta, Ohio on April 17, 1861. Company D organized at McArthur, Ohio on April 18, 1861. Company F originated at Gallipolis, Ohio on April 22, 1861. Company I formed at Jackson, Ohio on April 24, 1861. Company K formed at Beverly, Ohio on April 23, 1861. Company G and H organized on April 22 and April 23, 1861 respectively. The State of Ohio formally mustered the regiment into service for three months of duty on May 26, 27, and 28, 1861, with the effective muster date being the individual company's organization date in April 1861. Two companies mustered into service at Camp Scott at Athens, Ohio; six companies mustered in at Camp Putnam at Marietta; and the final two companies mustered in at Parkersburg, Virginia (modern-day West Virginia).
In May 1861, the 18th Regiment departed for Parkersburg, Virginia (modern-day West Virginia), where officials dispatched portions of the regiment to different locations on the Baltimore and Ohio Railroad between Parkersburg and Clarksburg, Virginia (modern-day West Virginia). The 18th guarded the railroad, escorted supply trains, hunted Southern guerrillas, constructed telegraph lines, and conducted various reconnaissance missions.
In mid August 1861, the 18th Regiment Ohio Volunteer Infantry received orders to travel to Columbus, Ohio, where officials mustered the regiment out of service on August 28, 1861. During its term of service, the regiment had one man die from disease and one man killed in a railroad accident.