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Federal
Map of Arsenic concentrations in groundwater of the United States
Department of the Interior —
The map graphic image at https://www.sciencebase.gov/catalog/file/get/63140561d34e36012efa2b7f?name=arsenic_map.png illustrates arsenic values, in micrograms per... -
Federal
TIGER/Line Shapefile, 2018, nation, U.S., Current County and Equivalent National Shapefile
U.S. Census Bureau, Department of Commerce —
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...