You can use the address where you last resided in the United States, even if that address no longer exists. While this will not affect your right to vote, you will need to provide an explanation of the situation to your local election official in the U.S.
When you generate your Voter Registration/Absentee Ballot Request form on our website, in the "Last U.S. Residence Address" section of the online process, you should provide the address where you last resided in the United States, even if it is no longer an existing address.
Then, in the "Additional Information" field that will appear later in the online process, you can explain why that address to no longer exists.
For example: "The address in [city/town] that I provided was the house where I resided when I lived in the U.S. before moving overseas, almost four decades ago. Since then, however, a shopping mall has been built over that location, so the street no longer exists."