Map of the conterminous United States showing routes of the principal explorers from 1501 to 1844, whose work had an important bearing on the settlement of the country and the fixing of its successive boundaries
1 : 8500000 "Taken from Bulletin 1212, Plate 1."
Original title: United States map showing routes of principal explorers and early roads and highways. Bond, Frank, 1856-1940 United States. General Land Office.; Geological Survey (U.S.); Reston, Virginia : U.S. Geological Survey