Unique Property Reference Number (UPRN) The new version of the API will soon enable you to search for an address using the UPRN. This is a code that identifies specific geographical locations down to a lower level than just the street address. It can be used to sub-divide shared buildings and can even be associated with cash points and other unique properties to aid localisation in the delivery of technology and connectivity. UPRNs are issued by local government bodies from the number ranges provided to them.