Riverdale Country School is a co-educational, independent, college-preparatory day school in New York City serving pre-kindergarten through twelfth grade. It is located on two campuses covering more than in the Riverdale section of the Bronx, New York, United States. Started as a school for boys, Riverdale Country School became fully coeducational in 1972. It currently serves 1,140 students. According to Niche's 2023 Private School Rankings, Riverdale is ranked the 2nd best private high school in New York City and the 3rd best private K-12 school in the United States. History Founded in 1907 by Frank Sutliff Hackett (1878–1952) and his first wife, Francis Dean (Allen) Hackett, Riverdale Country School is one of the oldest country day schools in the United States. Originally known as the Riverdale School for Boys, it began with 12 students and four teachers and promised scholarly, intimate teaching amid abundant recreational space. Describing his school as "an American experiment in education," Hackett later told The New York Times: "We have tried to transform schools from mere nurseries of the brain into a means of nourishing the whole boy — mind, body, and spirit." An early advocate of outdoor experiences for young people, Hackett started a summer camp known as Camp Riverdale at Long Lake in the Adirondacks (1912–1964) to provide summer recreation for his students. By 1920, Hackett had acquired three acres on Fieldston Road for the school and built a classroom building and dormitory. The 100-room dormitory, designed by McKim, Mead, and White, later became known as Hackett Hall. In 1924, he started the Neighborhood School for boys and girls from grades one to three, and in 1933, the Riverdale Girls School. By World War II, the school attracted both day students and boarders; one student in six or seven came from another country. Hackett dreamed of expanding the school into an "American World School" and acquired a new site in Riverdale. In 1948, Gen. Dwight Eisenhower, then president of Columbia University, spoke at a dedication ceremony at the site. Hackett died before his dream was realized, and the property was sold. In 1972, the Boys and Girls Schools were combined. In 1985, the Middle and Upper Schools were consolidated on the Hill Campus and the Lower School moved to the River Campus. Hackett was an organizer of the Guild of Independent Schools of New York City, and an organizer and president of the Adirondack