America's oldest terrorist organization and one of the most famous hate groups in the world, the Ku Klux Klan was founded in Pulaski, Tennessee as a fraternity for Confederate veterans shortly after the [[TheAmericanCivilWar Civil War]]. The members quickly turned to violence towards newly freed blacks. Terrorizing blacks and Northerners, the KKK became a dire threat to Reconstruction, but was put down in the 1870s, only to resurface in the 1910s.
The new Klan was formed as a response to immigrants from Eastern Europe, most of whom were either Catholic or Jewish, although they still continued their violence towards African-Americans. In the 1920s, the KKK had over 4,000,000 members in the United States and pulled in a lot of political influence, but waned in both power and numbers during the Great Depression and World War II, only to resurge in the 1950s and 1960s to fight the Civil Rights movement.
In the 1970s, the Ku Klux Klan decentralized and broke off into various splinter groups. The hatred towards Catholics has died off in most Klan groups (save for a few), but the hatred towards black people, Jews, and immigrants remain. With changing dynamics, these immigrants are now mostly Latino instead of Eastern European, and now Muslims, liberals, and LGBT individuals are added to the list of people hated by the various KKK splinter groups.
There are four distinct Klans, each with their own history.
* The First Klan (1865-1872): The earliest Klan group, founded by Confederate veterans that quickly became a hate group and America's first terrorist organization. EarlyInstallmentWeirdness is in effect for this group, as much of the imagery associated with the KKK (white robes, conical hats, the Confederate Flag) is largely absent. The First Klan did wear masks and hoods to conceal their identity though, and the title of Grand Wizard (the chief leader of the Klan) originated here.
* The Second Klan (1915-1944): The most powerful and arguably most well-known iteration of the Ku Klux Klan, the Second Klan was founded as a response to the waves of immigrants from Eastern Europe, most of whom were either Catholic or Jewish, as well as [[TheRedStapler inspiration]] from the film ''Film/TheBirthOfANation'' which glorified the First Klan. Membership peaked at six million in 1924 (one year before the Klan's famous parade through Washington, D.C.) but a series of scandals -- most notably the rape, murder, and apparent cannibalism trial of Indiana Grand Dragon D.C. Stephenson -- destroyed the Klan's reputation as defenders of law and order, sending it into decline during the late '20s and '30s. They finally died out in 1944. A lot of the common images of the Klan, such as conical hats, white robes, and burning crosses, started here. Klan violence during this time also led to the formation of the Jewish Anti-Defamation League, today one of the chief civil rights/anti-racism organizations.
* The Third Klan (1945-1970s): The Third Klan was formed to combat the CivilRightsMovement, gaining power in the 1950s and 1960s. It was also the last fully unified Ku Klux Klan. Hatred towards Jews and Catholics continued, but the main focus once again shifted to black people. Sometime around the mid-1970s, after the success of Civil Rights legislation and increasing pressure from the FBI and local police, the KKK fizzled out and splintered into various smaller groups. By 1980, there was no unified Klan.
* The Fourth Klan (1970s-Present Day): The current Klan, or more accurately, Klans. This generation of the Ku Klux Klan is different from any previous generation, namely due to lack of unity, close connections with Neo-Nazis, and loosening of membership restrictions. While the First and Second Klans only considered [[WhiteAngloSaxonProtestant Anglo-Saxon Protestants]] (and, occasionally, Scottish and Irish Protestants) to be "white", most modern Klan groups will allow any white supremacist to join, and many Klan groups such as the Imperial Klans of America even accept Catholics. The targets and style of their violence have also changed. The lynchings and cross-burnings have been largely replaced with brutal but isolated beatings of innocent people and other hate crimes, and most of their violence is directed against Latinos, Muslims, and LGBT people, though Jews and Blacks are still ripe for targeting. This Klan operates less like a terrorist organization and more like a loose group of disorganized crime gangs, further solidifying their unity with skinheads and other Neo-Nazis. Over 32 groups claim to be Ku Klux Klan orders.
Traditionally, the KKK has been associated with the DeepSouth, but this is only really true of the First and Third Klans. The Second Klan was a nation-wide organization (Indiana was the state the KKK dominated most in the 1920s), and more modern Klan groups are focused mainly in the Midwest as well as the South, with some chapters in Europe and reports of Klan groups as far away as South Africa and Russia.
Beginning in the 1920s, it's become fairly common for the KKK to be referred to as "fascist", with [[EaglelandOsmosis some observers even theorizing that fascism must have begun in America since the Klan preceded Mussolini and Hitler by over half a century]]. This is probably due to the popular "racism equals fascism" fallacy. While it is true that the second incarnation of the Klan (and, to a lesser extent, subsequent Klans) displayed an extreme form of patriotism not unlike the nationalism found in fascist countries, there have been two important differences. First, fascism is (usually) a strictly secular philosophy, and from the very beginning all forms of the Klan have trafficked in religious or at least supernatural imagery. Second, fascism is very statist (focused on centralization of a nation's government), while the original incarnation of the Klan was, in part, a ''regionalist'' backlash against the statist policies of Reconstruction.
See also TheKlan, which is a trope portraying the Ku Klux Klan and similar groups in fiction.