United States Post

United States Post is a courier delivery services company in Grand Theft Auto V and Grand Theft Auto Online.

Description
The company owns a warehouse at the Terminal, in the Port of Los Santos, and USP mailboxes can be usually found around San Andreas. It is most likely based on the United States Postal Service, having a very similar name and logotype.

It is unknown if United States Post is a government agency like its real-life counterpart, or a private company like GoPostal or Post Op. The presence of mailboxes on public property points towards the former.