Year 1870 (MDCCCLXX) was a common year starting on Saturday (link will display the full calendar) of the Gregorian calendar and a common year starting on Thursday of the 12-day slower Julian calendar.

African Americans (also referred to as Black Americans or Afro-Americans, and formerly as American Negroes) are citizens or residents of the United States that have ancestry from any of the native populations of Sub-Saharan Africa.

African Americans make up the single largest racial minority in the United States. Most African Americans are of West and Central African descent and are descendants of enslaved Africans within the boundaries of the present United States. However, some immigrants from African, Caribbean, Central American or South American nations, or their descendants, may be identified or self-identify with the term.

African-American history starts in the 16th century with African slaves who quickly rose up against the Spanish explorer Lucas Vázquez de Ayllón and progresses to the present day, with Barack Obama as the 44th and current President of the United States. Between those landmarks there have been events and issues, both resolved and ongoing, including slavery, racism, Reconstruction, development of the African-American community, participation in the great military conflicts of the United States, racial segregation, and the Civil Rights Movement.