The original Ku Klux Klan declined in in the late 1860s/early 1870s for several reasons, including an order by "Grand Wizard" Nathan Bedford Forrest for the group to disband because of its excessive violence. Branches, however, remained active and urged Congress to pass the Force Act (1870) and the Ku Klux Act (1871)
Sources: http://www.africanamericans.com/KuKluxKlan.htm
In the 1920s, the Ku Klux Klan mainly existed in the northern part of the United States. It opposed Blacks, Catholics, and Communists. The main reason was because those people were taking their jobs. The Southern farms were industrializing and had an excess of labor. Both Blacks and Whites were moving North. Southern Europeans were mainly Catholics and were coming to America taking jobs in mines and factories. Communists and Anarchists were fleeing the chaos they had created in Russia and the Balkans.
When congress passed Immigration laws, that stopped the Southern and Eastern Europeans from taking jobs away from Americans. New Cotton Mills in the South started absorbing Southern Labor. Without an economic reason for existence, the Klan declined.
The Klan started losing popularity in the 20th Century because of WW1 and WW2, as well as Truman's desegregation of the Armed Services. Education played a role also but, from WW2 onward the Klan was fighting a rearguard action. Too many white Americans had worked closely with, and indeed owed their lives to, black Americans for the Klan to make sense to them.
Case in point, in the then segregated Marine Corps (all the Services were segregated at the time) on that awful battle of Iwo Jima the black Marines were "laborers". And, yet, when the fighting was at it's worst the black Marines of the Ammunition Companies became stretcher bearers and, those black Marines went after the wounded, being killed and wounded themselves.
Tough to listen to the nonsense from the Klan after being one of those Marines. Or bomber crews after the Tuskeegee Airmen. Or ...
Black Americans, after their service in both World Wars were also much less likely to be so subservient. One of the tragedies of American education is that almost nothing is known of the black American Infantry Regiments that were placed under French command during WW1, nor of the Black Infantry and Cavalry Regiments of the Indian Wars.
The leader was found guilty of moral and legal violations and disgraced.
The Klan of the 1920s was strongest in Indiana.
The Zulu Tribe.
Immigrants and religion
Georgia?
Most Klan members were Protestants.
Tennessee.
The Ku Klux Klan.
Klu Klux Klan began in 1865, end of Civil War.
The Ku Klux Klan had a resurgence during that time.
If there are, they should leave.
They had friends in High places
what was the klu klux klan