Let me confuse you! Hanover is mostly located in Anne Arundel - however, a portion of it is acutally in Howard County! That oddball location is where I live. There are 2 local post offices in my area, equal distance away, and our mail keeps getting tossed from one to the other depending on what the postmaster general declares our neighborhood to be assigned too.
It doesn't affect us much, unless you have a package or envelope that needs a signature and you have to go to the counter to pick it up! Those items are always at the post office I didn't drive too!