This is a nifty, uncommon cover sent from Philadelphia, Pennsylvania, to an L.L. Sweeny, at the University of Virginia, Charlottesville, Virginia, U.S.A., on January 22, 1866(or 1868). Interestingly, the envelope was customized(suggesting an ongoing, frequent correspondence!) and it cost 10-Cents to send the mail, suggesting that there might have been some money sent. The sender was L.L. Sweeny's mother. He was likely a student or professor there, but I wasn't been able to find anything online about him.
To continue, the green, 10-Cent Washington issue is in fine condition! The fancy cancel and small, CDS from the Philadelphia P.O. are not too bad, but are smudged and/or a bit light. The transit duplex from another Philadelphia P.O. on the back is pretty nice, but light/faded in areas.
Lastly, as for the manila envelope, it's in pretty good condition for something around 164 years old. It's pretty clean. The envelope does have some creases in it here and there, and the top and bottom sides are torn open a bit. That happened when the mail was opened so long ago. The envelope was also reduced some at that time, too. The back flap is about 90% intact, though. Noted imperfections aside, this is still a neat, unique piece of post-Civil War, U.S. postal history.