check_data_package      Check whether to install USAboundariesData and
                        install if necessary
install_USAboundariesData
                        Install the 'USAboundariesData' package after
                        checking with the user
state_codes             State codes and abbreviations for U.S. states
                        and territories
state_plane             Projections from the State Plane Coordinate
                        System
state_proj              Data for projections from the State Plane
                        Coordinate System
states_contemporary_lores
                        U.S. state boundaries
us_cities               City locations and populations (historical and
                        contemporary)
us_congressional        Congressional district boundaries
                        (contemporary)
us_counties             County boundaries (contemporary and historical)
us_states               State boundaries (contemporary and historical)
us_zipcodes             Zip Code Tabulation Areas (contemporary)
