Why do I have to prove old address for my passport?

Passport! Physical Address?

• I looked on the website here: http://travel.state.gov/passport/passport_1738.html But I cannot find where it say's I need proof of my physical address. (Maybe I browsed it too easily) Problem is I don't have proof. I always use a P.O. Box. Always. For all bills, bank statement. Even on my tax form. I do not know how to prove it... Any other ideas? Or does anybody really know if I do need proof of my physical address for a passport? Please and thank you.

• Answer:

  You will have to submit a copy of your driver's license or State ID card. Both of those have a physical address. Also, your tax return if you file would have a physical address. The IRS doesn't allow you to just have a P.O. Box, you can do that for where the refund is going but a real physical address is required. A copy of your birth certificate is also required! Go to your local post office most of them have the ability to answer passport questions!!