Subject
United States Description and travel
113
United States Discovery and exploration
78
United States History
46
West (U.S.) Description and travel
32
United States Politics and government
30
United States Foreign relations
29
Indians of North America
22
United States Boundaries
22
United States History Regimental histories
21
Canada Description and travel
17
Mexico Boundaries
15
United States
14
Mexican War, 1846-1848
12
Mexico Foreign relations
12
Mississippi River Valley Description and travel
12
United States Commerce
11
Geology
10
Natural history
10
Frontier and pioneer life
9
Hunting
9
Louisiana History
9
Slavery
9
Colorado River (Colo.-Mexico)
8
Northwest, Old Description and travel
8
Postal service
8
Railroads
8
Texas History
8
United States Emigration and immigration
8
Mexico Description and travel
7
Southwest, New Description and travel
7
Spain Foreign relations
7
Texas Annexation to the United States
7
Fur trade
6
Indians of North America Wars
6
Louisiana Purchase
6
Ohio River Valley Description and travel
6
Overland journeys to the Pacific
6
Texas Description and travel
6
United States Social life and customs
6
Germans
5
Habeas corpus
5
Martial law
5
Missions
5
Mississippi River Description and travel
5
Montana Description and travel
5
Public lands
5
Rocky Mountains
5
Alaska Description and travel
4
Latter Day Saints
4
Mines and mineral resources
4
more ...