In 1909 a group of African Americans, including Ida B. Wells, joined with whites in organizing a national organization to fight segregation. It was named the National Association for the Advancement of Colored People (NAACP). The group began to organize branches in states including ones in the South.
Eventually the NAACP turned its fight against segregation to the courts. Here they were ultimately successful when the U.S. Supreme Court outlawed segregation in schools in a ruling in 1954.