USAboundaries           USAboundaries: Historical boundaries of the
                        United States of America, 1629-2000
hist_us_counties        Boundaries of counties in the United States of
                        America, 1629-2000
hist_us_states          Boundaries of states in the United States of
                        America, 1783-2000
us_boundaries           Get the boundaries of the United States for a
                        particular date
