U.S. county boundaries GIS shapefile by Mapdiva, LLC contributed to Natural Earth public domain map dataset

This map layer portrays the county boundaries of the United States, Puerto Rico, and the U.S. Virgin Islands, by showing the counties as areas, simplified and aligned for use with the Natural Earth Data 1:10m large-scale data. Mapdiva, LLC created the layer from the USGS National Atlas 1:1,000,000-Scale County Boundaries of the United States 201403 Shapefile source file. The file was simplified to 1:10m scale and aligned to the Natural Earth Data (v4) 1:10m Admin-1 US States boundaries and the Natural Earth Data (v4) 1:10m Rivers + lake centerlines. Mapdiva, LLC, makers of Ortelius(TM) map design software for macOS, contributed this dataset to Natural Earth.
Natural Earth is a public domain map dataset available at 1:10m, 1:50m, and 1:110 million scales. Featuring tightly integrated vector and raster data, with Natural Earth you can make a variety of visually pleasing, well-crafted maps with cartography or GIS software. This dataset is designed for use with U.S. State templates in Ortelius(TM) cartography software for the Mac, contributed in the public domain by Mapdiva, LLC.