The USPS has GPS data with the precise location that a delivered package was scanned by the postal carrier at the time of delivery. That GPS data is accurate to within a few feet in our neighborhood. In our most recent case, I could tell that the postal carrier scanned a missing package as they got out of the truck in front of a neighbor's house, before walking ~20 feet and dropping the package at their front door. (The misdelivered package arrived with a pile of other packages for the neighbor that day. The neighbor had not opened the packages and did not notice that my package was in the mix.)
You should call USPS with the tracking number. Be prepared to wait on hold. Explain that the package is listed as delivered, but you never received it, and would like to know the GPS coordinates of the delivery. They should have the information you need. If they give you the coordinates, you can look them up in Google Maps. They may give you the address instead. They may not give you any information; they may insist on initiating a trace or whatever they call it. Try "sweet talking" the USPS support person (we usually call it "social engineering"). They may reveal the address or GPS coordinates where the package was delivered. Talk with your postal carrier - they may be able to help, too.
