It depends on how you define "end of the war". Is the end of war when the shooting stops, or when the diplomats sign the paperwork?
http://en.wikipedia.org/wiki/List_of...c_irregularity
The last town of the Confederate States of America:
http://en.wikipedia.org/wiki/Town_Line,_New_York
It rejoined the Union in 1946. Does that mean the American Civil War was still ongoing?