Brown v. Board of Education

 The Topeka junior high schools had been integrated since 1941. Topeka High School was integrated from its inception in 1871 and its sports teams from 1949 onwards.[66] The Kansas law permitting segregated schools allowed them only "below the high school level".[67]  Soon after the district court decision, election outcomes and the political climate in Topeka changed. The Board of Education of Topeka began to end segregation in the Topeka elementary schools in August 1953, integrating two attendance districts. All the Topeka elementary schools were changed to neighborhood attendance centers in January 1956, although existing students were allowed to continue attending their prior assigned schools at their option.[68][69][70] Plaintiff Zelma Henderson, in a 2004 interview, recalled that no demonstrations or tumult accompanied desegregation in Topeka's schools...

https://en.wikipedia.org/wiki/Brown_v._Board_of_Education

The Brown ruling directly affected legally segregated schools in twenty-one states. In 1954, seventeen states had laws requiring segregated schools (Texas, Oklahoma, Missouri, Arkansas, Louisiana, Mississippi, Alabama, South Carolina, Georgia, Florida, North Carolina, Tennessee, Kentucky, Virginia, West Virginia, Maryland, and Delaware), and four other states had laws permitting rather than requiring segregated schools (Kansas, Arizona, New Mexico, and Wyoming). Kansas's state statutes restricted segregated elementary schools only to cities, such as Topeka, that had populations of more than fifteen thousand.

https://www.archives.gov/publications/prologue/2004/spring/brown-v-board-1.html