Territorial expansion 70 History 37 Foreign relations 12 Frontier and pioneer life 12 Politics and government 9 Expansion territoriale 6 Indians of North America 6 more ... Slavery 6 Colonial question 5 Government relations 5 Histoire 5 Imperialism 5 Race relations 4 Discovery and exploration 3 Eastern question (Far East) 3 Explorers 3 Extension to the territories 3 Historical geography 3 Mexican War, 1846-1848 3 Public opinion 3 Spanish-American War, 1898 3 Causes 2 Colonization 2 Diplomatic relations 2 Discoveries in geography 2 Filibusters 2 HISTORY 2 Immigration and emigration 2 Insular possessions 2 Land settlement 2 Louisiana Purchase 2 Politique et gouvernement 2 Presidents 2 Public lands 2 Social aspects 2 Sources 2 20e s. (1ère moitié) 1 African American 1 African Americans 1 Américain d'origine hispano-américaine (peuple) 1 less ...