Hessian Hills School (1925–1952) was a progressive school in the Mount Airy neighborhood of Croton-on-Hudson, New York. The school was founded as a community school by Elizabeth Moos and Margaret Hatfield. Children were welcomed from age 2 to 15. In 1934, Hessian Hills School, City and Country School in New York City, and five other like-minded progressive schools formed a group called Associated Experimental Schools to raise funds and to refine their progressive philosophy, but the group was abandoned by the end of the 1930s. City and Country School has preserved the archives of this group.