Postal inquiry?

Question

Is a return address required on the envelope of a letter being mailed in the U.S.?

Answer 1

If you take it to a post office they will require one. If you drop it in box somewhere else for them to pick up there isn't much they can do about it but if it is undeliverable, they don't know who to return it to and it will just go into a "Dead Letter File".

Answer 2

No, a return address is not required but the lack of one prevents the postal service from being able to return the package(s)/letter(s) in the case it is undeliverable.