During reconstruction and with the attempts to integrate black and white society, there was staunch resistance, primarily from former confederate and democrat members. Many of these folks banded together into groups to oppose different aspects of reconstruction. For instance, the KKK, the oldest of these institutions, banded together in 1865 in Tennessee to fight any attempts to raise the status of African Americans.
In 1867 the Knights of the White Camellia was formed by mostly upper class democratic society and confederacy to push back against reconstruction and support white supremacy.
In 1874, in order to intimidate republicans and freedman, the White Man's League was formed in Louisiana to combat reconstruction and prevent freedman from voting. It also had the goal of getting republicans out of office.
Research the topic online. There are MANY historical sites that can give you tons of information on these groups that will help with this topic and go into much greater detail. I have only scratched the surface of what you can find to answer the question.