The Ku Klux Klan (KKK; ), sometimes referred to as the Klan, is an American Protestant-led white supremacist and far-right hate group. Historians widely identify it as one of the earliest terrorist groups in the United States, citing its organized use of violence and intimidation to influence political and social conditions, particularly in the post-Civil War South. Across its three major iterations, the Klan has operated as a secret society made up of multiple affiliated organizations that used threats, assaults, and killings to advance their aims. Over its various eras, its targets included African Americans, Jews, Catholics, and immigrants.
The first Klan emerged during Reconstruction, founded by former Confederate soldiers who opposed federal efforts to extend civil and political rights to formerly enslaved people. It carried out widespread violence against black voters, officeholders, and their white allies in an effort to undermine Republican state governments and restore white Democratic control in the South. Federal Enforcement Acts and prosecutions beginning in 1871 significantly weakened this iteration. A second Klan, founded in 1915 and reaching its peak in the 1920s, expanded beyond the South and attracted millions of members from segments of the native-born white Protestant population. It promoted nativism, racial segregation, and "100 percent Americanism," and engaged in intimidation and, at times, mob violence. A third wave arose in the mid-20th century in response to the civil rights movement; although smaller, it included groups that carried out acts of racial terror aimed at resisting desegregation and racial equality.
Despite differences in size and structure, all iterations shared core ideological elements, including white supremacy, racial segregation, and hostility toward perceived outsiders. Over time, Klan groups espoused positions associated with white nationalism, anti-immigration nativism, antisemitism, anti-Catholicism, anti-communism, homophobia, Islamophobia, and opposition to civil rights reforms. Some members framed their activities as defending "Americanism" and Christian morality, and certain local chapters sought social respectability through parades, charitable events, and political organizing. Major Christian denominations, including leading Protestant bodies, formally condemned the Klan's ideology and methods as incompatible with Christian theology.
The Klan is widely viewed as a violent extremist movement that contributed to systematic racial oppression and domestic terrorism. Modern scholarship has documented its extensive use of intimidation, lynching, and political violence, emphasizing its long-term impact on American history. Earlier supporters offered alternative interpretations, portraying the Klan as a patriotic or law-and-order organization responding to social or political upheaval. They cited agreement with its racial policies, approval of its fraternal or charitable activities, and the belief that it upheld "law and public morality." Historians generally contrast these justifications with extensive records of Klan violence and coercion, highlighting the gap between the organization's self‑presentation and its documented actions.
The first Klan was founded in Pulaski, Tennessee, on December 24, 1865, by six former officers of the Confederate Army: Frank McCord, Richard Reed, John Lester, John Kennedy, J. Calvin Jones, and James Crowe. It began as a fraternal social club inspired in part by the then largely defunct Sons of Malta. According to The Cyclopædia of Fraternities (1907), the group borrowed elements of its initiation ceremonies from that organization, with the same stated purpose: "ludicrous initiations, the baffling of public curiosity, and amusement for members", in which "in each of these directions it was singularly successful". The manual of rituals was printed by Laps D. McCord of Pulaski. The origins of the hood are uncertain; it may have been adapted from the Spanish capirote hood, or it may derive from "folk traditions of carnival, circus, minstrelsy, Mardi Gras – or mid-century 'Calico Indians'" associated with the Anti-Rent War in upstate New York.
The Cyclopædia of Fraternities (1907) also stated: "Beginning in April, 1867, there was a gradual transformation. ... The members had conjured up a veritable Frankenstein. They had played with an engine of power and mystery, though organized on entirely innocent lines, and found themselves overcome by a belief that something must lie behind it all—that there was, after all, a serious purpose, a work for the Klan to do."
The KKK had no organizational structure above the chapter level. However, similar groups across the South adopted comparable goals. Klan chapters promoted white supremacy and spread throughout the region as an insurgent movement resisting Reconstruction. Confederate veteran John W. Morton founded a Klan chapter in Nashville, Tennessee. As a secret vigilante organization, the Klan targeted freedmen and their allies, seeking to restore white supremacy through threats and violence, including murder. According to J. Michael Martinez, the Klan "targeted white Northern leaders, Southern sympathizers and politically active blacks." In 1870 and 1871, the federal government passed the Enforcement Acts, which were designed to prosecute and suppress Klan crimes.
The first Klan had mixed results in achieving its objectives; although it significantly weakened black political leadership through assassinations and threats of violence, driving some individuals out of public life, it also provoked a strong backlash, including the passage of federal legislation that historian Eric Foner describes as successful in "restoring order, reinvigorating the morale of Southern Republicans, and enabling blacks to exercise their rights as citizens". Historian George C. Rable argues that the Klan was ultimately a political failure and was therefore abandoned by Democratic Party leaders in the South. He writes:
The Klan declined in strength in part because of internal weaknesses; its lack of central organization and the failure of its leaders to control criminal elements and sadists. More fundamentally, it declined because it failed to achieve its central objective – the overthrow of Republican state governments in the South.
After the Klan was suppressed, similar insurgent paramilitary groups emerged that were explicitly dedicated to suppressing Republican voting and removing Republicans from office. These included the White League, founded in Louisiana in 1874, and the Red Shirts, which originated in Mississippi and later developed chapters in the Carolinas. The Red Shirts, for example, are credited with helping elect Wade Hampton as governor in South Carolina, acting as the military arm of the Democratic Party and contributing to the restoration of white Democratic control of state legislatures throughout the South. According to Historian George C. Rable, the Red Shirts "formed a solid line around the ballot boxes and prevented Negros without Democratic tickets from approaching", and even when federal troops attempted to clear a path, "many had gone home".
In 1915, the second Klan was founded atop Stone Mountain, Georgia, by William Joseph Simmons. While Simmons relied on documents from the original Klan and on the recollections of surviving members, the revived organization drew significant inspiration from the film The Birth of a Nation. The earlier Klan had not worn white costumes or burned crosses; these elements were introduced in Thomas Dixon's 1905 fictional novel The Clansman: A Historical Romance of the Ku Klux Klan, on which the film was based. When the film was shown in Atlanta in December of that year, Simmons and his new Klansmen paraded to the theater in robes and pointed hoods—many on robed horses—mirroring the imagery depicted in the film. These mass parades became a hallmark of the new Klan that had not existed in the first iteration.
Beginning in 1921, the second Klan adopted a modern business system that relied on full-time, paid recruiters, and it appealed to prospective members as a fraternal organization similar to many others flourishing at the time. The national headquarters profited from a monopoly on costume sales, while organizers retained initiation fees. The organization grew rapidly nationwide during a period of economic prosperity.