根据美国刑法第194条（ § 194 of the Criminal Code）

“and under and in supplement of § 194 of the Criminal Code, the Postmaster General, by a general order, may designate as letter boxes for the receipt or delivery of mail matter all letter boxes and other receptacles which are so used or intended on city delivery or other mail route, a privately owned box coming within such designation is an "authorized depository for mail matter" within the meaning of the penal section, and a theft of letter from such a box is punishable as the section prescribes. So held where the letters were stolen from boxes placed by tenants for receipt of mail in the halls of buildings in which they had their place of business. The boxes bore the names of the owner and were not locked. Mail was deposited in them by the carriers, but not collected from them.”