Internal, first-order administrative boundaries and polygons for the United States (.shp), converted to .geojson (QGIS), and .topojson (http://mapshaper.org/). reference data here: http://www.naturalearthdata.com/downloads/110m-cultural-vectors/110m-admin-1-states-provinces/ and repo is here: https://github.com/nvkelso/natural-earth-vector/tree/master/110m_cultural