Cooper Hewitt, Smithsonian Design Museum located in New York City (2 East 91st St). Open 10:00 a.m. to 6:00 p.m. daily.Welcome to Cooper Hewitt, Smithsonian Design Museum. Cooper Hewitt is the only museum in the United States devoted exclusively to historical and contemporary design, and is the steward of one of the most diverse and comprehensive design collections in existence—more than 215,000 design objects spanning 30 centuries