Columbia subject headings:
Custis, Peter.
Dunbar, William, 1749-1810.
Freeman, Thomas, -1821.
Hunter, George, 1755-1823.
Lewis and Clark Expedition (1804-1806)
Pike, Zebulon Montgomery, 1779-1813.
United States--History--19th century.
United States--Territorial expansion.
West (U.S.)--Discovery and exploration.
Harvard subject headings:
Explorers--West (U.S.)--Biography
West (U.S.)--Discovery and exploration.
West (U.S.)--History--To 1848.
Princeton subject headings: