Subject
West (U.S.) Description and travel
23
Lewis and Clark National Historic Trail
12
West (U.S.) Discovery and exploration
10
Columbia River
8
Missouri River
8
Explorers
6
United States Discovery and exploration
6
West (U.S.)
6
Geomorphology
3
Hydrology
3
Indians of North America
3
Influence
3
Landforms
3
United States Territorial expansion
3
West (U.S.) Exploration
3
Centennial celebrations, etc
2
Clearwater National Forest (Idaho)
2
Cree language
2
Curricula
2
Historic sites
2
Indians of North America History Curricula
2
Lemhi County (Idaho)
2
Lewis and Clark National Historic Trail Curricula
2
Louisiana Purchase
2
Missouri
2
Montana Description and travel
2
Montana History
2
Natural history
2
Oregon History
2
Relations with Indians
2
United States Description and travel
2
West (U.S.) History
2
America Discovery and exploration Spanish
1
American Discovery Trail
1
Art, American
1
Automobile travel
1
Bird-Truax Trail (Idaho and Mont.)
1
Bird-Truax Trail (Idaho and Mont.) History
1
Birds
1
Boats and boating
1
Businessmen
1
Canada Description and travel
1
Cape Disappointment State Park (Wash.)
1
Cartography History
1
Culture conflict History
1
Diaries
1
Donner Party
1
Ecola State Park (Or.)
1
Enslaved persons
1
Ethnological collections
1
more ...