This polygon shapefile contains combined statistical areas in the United States and Puerto Rico. Combined statistical areas consist of two or more adjacent core based statistical areas (CBSAs) that have substantial employment interchange. The map layer was created from data produced by the U.S. Census Bureau. This layer is part of the 1997-2014 edition of the National Atlas of the United States. These data are intended for geographic display and analysis at the national level, and for large regional areas. The data should be displayed and analyzed at scales appropriate for 1:1,000,000-scale data. No responsibility is assumed by the National Atlas of the United States in the use of these data.