Columbia subject headings:
Blue Mountains (Or. and Wash.)--History--Sources.
Oregon National Historic Trail--History--Sources.
Oregon Territory--History.
Oregon--History--1859-
Harvard subject headings:
Blue Mountains Region (Or. and Wash.)--History.
Frontier and pioneer life--Blue Mountains Region (Or. and Wash.)
Oregon National Historic Trail.
Princeton subject headings:
Blue Mountains Region (Or. and Wash.)--History.
Frontier and pioneer life--Blue Mountains Region (Or. and Wash.).
Oregon National Historic Trail.