On a recent trip to the post office (insert reason why here: I was mailing a bunch of John Foley’s books out) I happen to notice that they have placed a large QR Code right on the front door.
The QR Code linked to their locations page of their website where you can enter a zip code or a state and locate all of the post offices in that area. This is a great use of a QR Code in my opinion.
Below is a picture of the QR Code that is on the front door of the post office.
And here is a screenshot of the locations page on the USPS website.