This is interesting. A Union Soldier held as a Prisoner of War in Helena, Arkansas in 1862 for 6 weeks before being exchanged? Is that what you are saying was your Grand uncle's experience?

Helena was occupied by Federal forces under the command of Union General Samuel Curtis on July 12th, 1862. Therefore, there would have been a very narrow window of time in which this particular set of circumstances could have occurred. Certainly the most logical explaination would have been that he was taken Prisoner of War from the Battle of Pea Ridge, and sent to Helena to await his exchange. Prisoner and Confederate wounded were sent to cities and towns all over the State to tend to their needs after that battle. This is about the only period of time that a Confederate military structure would have existed in Arkansas or Helena to have preformed such an exchange. Helena would have been a natural place for an exchange of Prisoners to have been held being on the Mississippi and the availbility of river travel to aid that exchange.