The nadir of American race relations was the period in African-American history and the history of the United States from the end of Reconstruction in 1877 through the early 20th century, when racism in the country, and particularly anti-black racism, was more open and pronounced than it had ever been during any other period in the nation's history. During this period, African Americans lost access to many of the civil rights which they had gained during Reconstruction. Anti-black violence, lynchings, segregation, legalized racial discrimination, and expressions of white supremacy all increased. Asian Americans were also not spared from such sentiments.

Racism has been reflected in discriminatory laws, practices, and actions against "racial" or ethnic groups throughout the history of the United States. Since the early colonial era, White Americans have generally enjoyed legally or socially sanctioned privileges and rights which have been denied to members of various ethnic or minority groups at various times. European Americans have enjoyed advantages in matters of education, immigration, voting rights, citizenship, land acquisition, and criminal procedure.