This polygon shapefile depicts service wide boundary set for display and general analysis purposes. This layer is part of the 2014 National Transportation Atlas Database. The National Transportation Atlas Databases 2014 (NTAD2014) is a set of nationwide geographic datasets of transportation facilities, transportation networks, associated infrastructure and other political and administrative entities. These datasets include spatial information for transportation modal networks and intermodal terminals, as well as the re¬lated attribute information for these features. This data supports research, analysis, and decision-making across all transportation modes. It is most useful at the national level, but has major applications at regional, state and local scales throughout the transportation community. The data used to compile NTAD2014 was provided by our partners within the United States Department of Transportation (USDOT) and by other agencies throughout the United States Federal Government. These contributors are the actual data stewards and are ultimately responsible for the maintenance and accuracy of their data. This coverage displays National Park Service unit boundaries United States. Department of Transportation. Research and Innovative Technology Administration. (2014). Administrative Boundaries of National Park System Units, 2011. National Transportation Atlas Database 2014. Available at: http://purl.stanford.edu/mg196xb7926.