The Ku Klux Klan
The Southern Poverty Law Center reports, “The Ku Klux Klan, with its long history of violence, is the oldest and most infamous of American hate groups. Although Black Americans have typically been the Klan’s primary target, it also has attacked Jews, immigrants, members of the LGBTQ+ community and, until recently, Catholics.” 
The Ku Klux Klan dates back to the Reconstruction, when a Confederate veterans group created a social club in Pulaski, Tennessee.  The club became a hate group crusading for racial supremacy in the South while using scare tactics to intimidate freed slaves.
The Klan next appeared in 1915 near Atlanta, Georgia. “This second Klan peaked in the 1920s, when its membership exceeded 4,000,000 nationally, and profits rolled in from the sale of its memberships, regalia, costumes, publications, and rituals. A burning cross became the symbol of the new organization, and white-robed Klansmen participated in marches, parades, and nighttime cross burnings all over the country.” 
For more information, refer here for local connection of the Ku Klux Klan. “Ku Klux Klan,” Southern Poverty Law Center  “Ku Klux Klan, Hate Organization, United States,” Encyclopedia Britannica  Ibid.