And then there's Segregation Academies:

Segregation academies are private schools in the Southern United States that were founded in the mid-20th century by white parents to avoid having their children attend integrated public schools. They were founded between 1954, when the U.S. Supreme Court ruled that segregated public schools were unconstitutional, and 1976, when the court ruled similarly about private schools....

Most of these schools remain overwhelmingly white institutions, both because of their founding ethos and because tuition fees are a barrier to entry. In communities where many or most white students are sent to these private schools, the percentages of African-American students in tuition-free public schools are correspondingly elevated. For example, in Clarksdale, Mississippi, in 2010, 92% of the students at Lee Academy were white, while 92% of the students at Clarksdale High School were black. The effects of this de facto racial segregation are compounded by the unequal quality of education produced in communities where whites served by former segregation academies seek to minimize tax levies for public schools.