Paul,

You aren't kidding, this guy is hard to track. It looks like his birthyear changed from census-to-census and I didn't see a real match in the 1850 or 1860.

There was a John J. Trosper who served in a Union regiment in Missouri, but that's probably not your guy if Alabama gave him a pension later in life.

From what I've seen, he's probably the J.J. Trosper shown in Sander's Company of Missouri State Guards and later in Company G of the 1st-4th Consolidated Missouri Infantry formed as a result of the surrender of Vicksburg.

If you haven't already done so, I'd definitely send off for a copy of the pension application. It would be held at the Alabama Archives in Montgomery and, if Trosper filled it out, will probably give the county where he was born. Since he also lived in Mississippi, I'd check with their archives in Jackson and see if he filed one there. Don't forget to check for one under his widow's name, assuming she outlived him.

That's the best I can think of, hopefully you'll find something useful in those records.

Scott