A data.frame which contains a map of all 50 US States plus the District of Columbia. The shapefile was modified using QGIS in order to 1) remove Puerto Rico and 2) remove islands off of Alaska that crossed the antimeridian 3) renamed column "STATE" to "region".
Taken from the US Census 2010 Cartographic Boundary shapefiles page (https://www.census.gov/geo/maps-data/data/tiger-cart-boundary.html) in May 2014. The resolutions is 20m (20m = 1:20,000,000).
# render the map with ggplot2 library(ggplot2) data(state.map) ggplot(state.map, aes(long, lat, group=group)) + geom_polygon()