When the Civil War began on April 12, 1861, with an attack on Fort Sumter, S.C., President Abraham Lincoln issued a call for 75,000 men to suppress a rebellion that threatened to tear apart the United States.

When the Civil War began on April 12, 1861, with an attack on Fort Sumter, S.C., President Abraham Lincoln issued a call for 75,000 men to suppress a rebellion that threatened to tear apart the United States.

It soon became apparent to Lincoln and most of the people trying to hold the Union together that Ohio would play a crucial role in the contest to come. Ohio had a population generally quite loyal to the Union cause and an excellent rail system connecting the state to much of the rest of the country.

When calls for troops were soon answered by two, three and even four times the number of people sought, it was apparent that Ohio would play a major role in winning the Civil War for the North.

By the end of the war, more than 160 regiments of cavalry, artillery and infantry -- of several hundred men each -- had been raised in Ohio to fight the war between the states. This prompted Lincoln at one point to say "Ohio has saved the Union."

In the weeks immediately after the outbreak of the war, hundreds of men traveled to Columbus to volunteer to fight for their country. And there was no place to put them. Men were housed in local schools, churches and even in the rotunda of the newly completed Statehouse.

Needing a place to keep all of these men, a place was soon found. Just to the north of the downtown was Goodale Park. Donated to the city by pioneer physician Lincoln Goodale in 1851, the park was mostly forest -- until April 1861. In short order, the trees were cut down and Camp Jackson was established.

It did not last long.

Rapidly filled with arriving volunteers, the camp was soon having problems coping with overcrowding, traffic and disposal of sewage. Clearly a bigger camp was needed.

That bigger camp was Camp Chase. Named for former Ohio Gov. Salmon P. Chase, it was located a few miles west of the city along West Broad Street. Camp Chase ran from Broad Street to Sullivant Avenue and encompassed several thousand acres of what had recently been quiet rural farmland.

As a mobilization and training center, Camp Chase was quite successful. It was so successful that by fall 1862 it was selected to be the site of a major Confederate prisoner of war camp. In that undertaking, it was not quite as successful.

Built to hold 2,000 men, by 1864 the Camp Chase prison camp held more than 10,000. Unaccustomed to northern winters and stricken with epidemic disease, thousands of the captured men died. More than 2,300 of them are buried there in one of the largest military cemeteries in the North. Each year on Confederate Memorial Day in June, a service is held at the Camp Chase cemetery at Hague and Sullivant avenues to remember them.

Camp Chase was the largest Union Army camp in Columbus and certainly the most noticeable with its prison camp. But it was not the only Union Army camp in the area.

Just within the immediate vicinity of Columbus, there were four more.

As early as 1861, it became apparent that the existing arsenal in what is now the Cultural Arts Center was inadequate. A new facility was acquired in what had previously been known as Robert Neil's Woods immediately to the northeast of downtown. In short order several new buildings were built on the new site, which would eventually come to be called Columbus Barracks. Renamed Fort Hayes in the 1880s, most of the site is now owned and operated by Columbus City Schools. In the center of the campus is the Shot Tower, the only building dating to the Civil War era.

Immediately north of downtown, Tod Barracks was constructed as an officers' residence and administrative facility in 1863. A historic marker near the Columbus Convention Center marks the location of the barracks complex.

The locations of two other Columbus area camps are a bit harder to find.

In April 1861, Col. Henry Beebe Carrington was given the task of organizing an entire new regiment of United States federal troops. A recruiting camp for the 18th United States Infantry was established on the farm of Solomon Beers on the east side of High Street south of its intersection with what is now Hudson Street. The camp lasted through the entirety of the war and was only abandoned in 1866. A few of its surviving buildings lasted until well into the 20th century.

It was perhaps because of the location of the 18th Infantry that Gen. Lew Wallace built a camp nearby that came to be named for him. No one ever doubted the courage or integrity of Lew Wallace. But because he had not been where he was supposed to be at the Battle of Shiloh in April 1862, he soon found himself in command of Camp Chase. His orders were to receive several hundred recently freed Union prisoners of war -- pay them, outfit them and send them to fight American Indians in Minnesota.

As one might imagine, many of these recently freed men were not exactly thrilled with the idea of going to Minnesota to fight the Sioux. In fact, many of them promptly deserted when told of their next assignment. To keep them together and under control, Wallace established a camp north and west of Camp Thomas. It did not last long and was not terribly effective at keeping the recently freed prisoners from deserting.

Lew Wallace soon moved on to other challenges. These included a distinguished record of combat leadership, service on the court that condemned the Lincoln murder conspirators, governor of the Arizona Territory and author of the biblical novel "Ben Hur."

At the end of the Civil War, the reorganized 18th United States Infantry left Camp Thomas and was sent west to build forts on the Bozeman Trail in northeast Wyoming.

One of Carrington's officers who had served with him in Columbus named William Fetterman claimed that with 80 men he could ride through the whole Sioux nation. In 1866, he tried to do that and 80 men died with him along the Bozeman Trail.

There are no markers in Columbus for Camp Thomas and Camp Lew Wallace. As the Civil War sesquicentennial approaches in 2011, perhaps there should be.

Ed Lentz writes a history column for ThisWeek.