Generating unique document identifiers from content within a selected page region is disclosed. A selection of a first region within a first page of the documents is received from a user, and is defined by a set of first boundaries relative to the first page. A text string of a first base selection page content within the first region is retrieved from the first page. Then the retrieved text string is assigned to a page location index associated with the first page. A text string of a first replicated selection page content is retrieved from a second page. The first replicated selection page content is included in the same first region defined by the set of first boundaries relative to the second page. The retrieved text string of the first replicated selection page content is assigned to a page location index of the second page.