Steve, the Compiled Service Records are individual extracts from larger documents, such as muster rolls, parole lists, hospital registers, etc., which were collected by the War Department during and after the war. Although a portion of the original documents were loaned to the War Department by various States and individuals after the war, the vast majority were captured during the war. During one of my visits to the National Archives several years ago, I asked a clerk where the originals were. He said that they were stored in a facility in the Washington area -- Maryland, I think -- and were no longer available to researchers because of their extremely deteriorated and fragile state of preservation. The Compiled Service Records had been microfilmed by that time, but most of the original documents had not been microfilmed.

About the 15th Arkansas Militia -- and the other Arkansas militia regiments -- these were not "one day" organizations. They constituted the existing prewar Arkansas State Militia. By law, the militia was required to muster once each year for annual inspection and drill. They continued to do so up through early 1862, after which the militia organization pretty much ceased to exist in most parts of the State. The roll for the 15th Militia (and the other regiments) which was extracted for the Compiled Service Records from the Spring 1862 annual muster. The sole exception is the roll of the 45th (Searcy County) Arkansas Militia. This was the only militia regiment actually called into active service during the Civil War. They were called up in November 1861 to track down and arrest suspected members of a "disloyal" organization known as the Arkansas Peace Society. They rounded up a number of suspects and marched them to Little Rock, where the detainees were "allowed" to enlist in the Confederate army. Most of them were enrolled as Companies I and K of Marmaduke's 18th Arkansas Regiment (later redesignated 3rd Confederate Infantry). Their job done, the 45th Militia returned to Searcy County and were mustered out of service. Most of the men later enlisted or were conscripted into the 27th Arkansas Infantry.

There were Camp Johnson's all over the South, and at least two that I know of in Arkansas -- one in Jefferson County and one in Benton County.