Do you vote absentee?  You must have a state residence to do that...don't you?  

If you don't vote absentee, U.S. congress critters won't give a rat's rear what you think.

Yes, I vote absentee.  And I use my last Congressional district. But the forms that institutions like construct are not constructed for me.  They wish an address in the states.  
I use my last address in the states. If the powers that be want to cross reference a city directory, they might ignore you, but in my experience they generally don't.