The 2015 cartographic boundary KMLs are simplified representations of selected geographic areas from the U.S. Census Bureau's Master Address File / Topologically Integrated Geographic Encoding and Referencing (MAF/TIGER) Database (MTDB). These boundary files are specifically designed for small-scale thematic mapping. When possible, generalization is performed with the intent to maintain the hierarchical relationships among geographies and to maintain the alignment of geographies within a file set for a given year. Geographic areas may not align with the same areas from another year. Some geographies are available as nation-based files while others are available only as state-based files.

                             In New England (Connecticut, Maine, Massachusetts, New Hampshire, Rhode Island, and Vermont), the Office of Management and Budget (OMB)
                             has defined an alternative county subdivision (generally cities and towns) based definition of Core Based Statistical Areas (CBSAs)
                             known as New England City and Town Areas (NECTAs).  NECTAs are defined using the same criteria as Metropolitan Statistical Areas and
                             Micropolitan Statistical Areas and are identified as either metropolitan or micropolitan, based, respectively, on the presence of
                             either an urban area of 50,000 or more population or an urban cluster of at least 10,000 and less than 50,000 population. A NECTA
                             containing a single core urban area with a population of at least 2.5 million may be subdivided to form smaller groupings of cities and
                             towns referred to as NECTA Divisions.

                             The generalized NECTA boundaries in this file are based on those defined by OMB based on the 2010 Census and published in 2013.