Many thanks for the info - I know much of this already, though not about Cox's Landing (Do you know where Cox's Landing was? And would prisoners really have been taken to Richmond at that late point in the war?). I have heard also about the "holding camps," where prisoners would be held until the numbers on the two sides "matched," whereupon the formal exchange would then take place. But what did that exchange actually look like? There seems to be no written record of that that I can find. The existence of the holding camps in places like City Point seems inconsistent with the idea that Confederate prisoners remained in Union hands until they were taken off the train in, say, South Carolina or Georgia. Were they simply herded from the holding camps onto box cars? Or were they actually released from Union custody there at the holding camp, once the numbers of parolees were equal for both sides?

I need to check with my reference source, which is a book on Point Lookout that contains several diaries, letters, and other documents relating to the prison; in one of those diaries the writer specifically says they were taken to City Point for exchange in early 1865. He does not mention how he got home. In another place a document states that while the exchanges were no longer taking place at Aiken's Landing by the spring of 1865, the clerk at Aiken's is the one who recorded the specific men who were exchanged and who kept tabs on the numbers to ensure an equal exchange.

I do know - the diary above mentions it - that the Union chose the sickest prisoners for exchange. Also, Grant requested that prisoners from states farther away - Tennessee, Arkansas, KY - be selected first as well, so that they would be less likely to be re-absorbed into the ranks. This would be consistent with them being put on trains to be taken to points farther South, but then you have the thing with the holding camps and how that was handled.

In trying to figure out this process, it's difficult to know which railroad lines were still intact and also in Union hands at the time - where would a prisoner who was from, say, Knoxville, have been shipped, and how? It's the "how" part that I can't seem to get any information for. What's to stop a soldier from getting off the train before he arrives at his destination? Was he still under guard at that point? And if he was sick, would he have been transported far away, or tended to at one of the five very large hospitals there at City Point?

As for my ancestor who was at Point Lookout, the 51st VA unit history says he was imprisoned at Camp Chase in Sept. 1864 and transferred to Point Lookout for exchange on 3/17/65. Family papers say only that he was imprisoned at Point Lookout. I do not know for certain how he got home; the family story is that he walked home and did not arrive until months after the war had ended. His name was William A. Terry. His brother, Nathan B. Terry, who was 2nd Lt. in the 51st, was imprisoned about the same time (Sept. 1864 - they were all captured in the Valley), first at the Old Capital Prison and then at Fort Delaware (12/17/64). He was not released until after the war (6/17/65 is the date we have for his parole). I do not know how he got home.