Columbia subject headings:
Harvard subject headings:
Frontier and pioneer life--West (U.S.)
Overland journeys to the Pacific
Trails--West (U.S.)--History.
West (U.S.)--Description and travel.
Princeton subject headings:
Frontier and pioneer life--West (U.S.)
Overland journeys to the Pacific.
Trails--West (U.S.)--History.
West (U.S.)--Description and travel.