The Hudson River Museum in Trevor Park, Yonkers, is Westchester County’s largest museum and is known for Hudson River School paintings, broad exhibitions in art, history, science, and regional heritage, and the county’s only public planetarium. Founded in 1919 as the Yonkers Museum, it moved in 1924 to Glenview, the former John Bond Trevor mansion, later adding a modern wing in 1969 and a new west wing in 2023. Its planetarium, first installed in 1956, has expanded repeatedly and remained central to public and school programs. Despite financial strain in the late 1980s and 1990s, the museum endured, expanded, and continued major educational, preservation, and community work.