The district was not de jure racially segregated, but by 1962, 94% of students at the Valley School were black, while no black children were enrolled the Plandome Road or Munsey Park schools in October of that school year, and all the black students who had previously attended these two schools had been the children of live-in domestics. Furthermore, socioeconomic disparities between residents of the Manhasset Valley School's attendance area and the residents of the other two rendered the parts of the school district outside of the Manhasset Valley area unaffordable for most of the families living in what was by that time a predominantly black neighborhood. The average levels of scholastic achievement at the Valley School were found to be significantly lower than at the district's other two elementary schools. As a consequence, the United States District Court for the Eastern District of New York found in Blocker v. Board of Education that the Manhasset elementary school zones were de facto racially segregated. Due to the Blocker decision, the elementary school attendance zones were redrawn, with the Manhasset Valley School closing at the conclusion of the 1963–64 school year and its students being rezoned to the Plandome Road School.
