The Lemon Grove Incident refers to a significant court case in 1931 in Lemon Grove, California, where a group of Mexican-American parents challenged the segregation of their children in schools. The local school board had established a separate school for Mexican children, claiming it was necessary for their education. The parents argued that this practice was discriminatory and violated their children's rights. In a landmark decision, the court ruled in favor of the parents, stating that the segregation was unconstitutional. This case was one of the first successful legal challenges against school segregation in the United States, setting a precedent for future civil rights cases.