History 21 Social aspects 8 Social conditions 4 Politics and government 3 Causes 2 Civilization 2 Group identity 2 more ... History and criticism 2 History, Military 2 Political aspects 2 African American troops 1 African Americans 1 American literature 1 Annexation to the United States 1 Apache Indians 1 Battlefields 1 Cinco de Mayo (Mexican holiday) 1 Civil rights 1 Climate 1 Cotton trade 1 Doniphan's Expedition, 1846-1847 1 Economic conditions 1 English language 1 Ethnic identity 1 Ethnic relations 1 Foreign economic relations 1 Fortification 1 Freed persons 1 Frontier and pioneer life 1 Gadsden Purchase 1 less ...