The TIGER/Line shapefiles and related database files (.dbf) are an extract of selected geographic and cartographic information from the U.S. Census Bureau's Master Address File / Topologically Integrated Geographic Encoding and Referencing (MAF/TIGER) Database (MTDB). The MTDB represents a seamless national file with no overlaps or gaps between parts, however, each TIGER/Line shapefile is designed to stand alone as an independent data set, or they can be combined to cover the entire nation.

           ANRCs are corporations created according to the Alaska Native Claims Settlement Act (Pub. L. 92–203 ' 85 Stat.688 (1971); 43 U.S.C. 1602 et
           seq. (2000)). They are organized under the laws of the State of Alaska as "Regional Corporations," to conduct both the for  profit and
           non-profit affairs of Alaska Natives within defined regions of Alaska. The Census Bureau treats ANRCs as legal geographic entities.  Twelve ANRCs cover
           the entire State of Alaska except for the area within the Annette Island Reserve (an American Indian Reservation under the governmental authority of the
           Metlakatla Indian Community). There is a thirteenth ANRC that represents the eligible Alaska Natives living outside of Alaska that are not members of any
           of the twelve ANRCs within the State of Alaska. Because it has no defined geographic extent, this thirteenth ANRC does not appear in the TIGER/Line
           Shapefiles and the Census Bureau does not provide data for it. The Census Bureau offers representatives of the twelve ANRCs the opportunity to review and
           update the ANRC boundaries. ANRCs are represented by a 5 character FIPS code unique within Alaska and a nationally unique 8 character National Standard
           (GNIS)code.