The map was modified using QGIS in order to remove Puerto Rico, islands off of Alaska that crossed the antimeridian and American Samoa. A column named "region" was added for convenience which is a duplicate of the column named ZCTA5CE10.

data(zip.map)

References

Taken from the US Census 2013 Cartographic Boundary Shapefiles - ZIP Code Tabulation Areas (ZCTAs): https://www.census.gov/geo/maps-data/data/cbf/cbf_zcta.html.