The "nadir of American race relations" was the period in the history of the Southern United States from the end of Reconstruction in 1877 through the early 20th century, when racism in the country was worse than in any other period after the American Civil War. During this period, African Americans lost many civil rights gains made during Reconstruction. Anti-black violence, lynchings, segregation, legal racial discrimination, and expressions of white supremacy increased.
Historian Rayford Logan coined the term in his 1954 book The Negro in American Life and Thought: The Nadir, 1877–1901. Logan tried to determine the year when "the Negro's status in American society" reached its lowest point. He argued for 1901, suggesting that relations improved after then. Others, such as John Hope Franklin and Henry Arthur Callis, argued for dates as late as 1923. (Logan, p. xxi)
The term continues to be used, most notably in the books of James Loewen, but also by other scholars. Loewen chooses later dates, arguing that the post-Reconstruction era was in fact one of widespread hope for racial equity due to idealistic Northern support for civil rights. In Loewen's view the true nadir began only when northern Republicans ceased supporting Southern blacks' rights around 1890, and lasted until the Second World War. This period followed the financial Panic of 1873 and a continuing decline in cotton prices. It overlapped with both the Gilded Age and the Progressive Era, and was characterized by the nationwide sundown town phenomenon.