The Smithsonian Institution, or simply the Smithsonian, is a group of museums, education and research centers, the largest such complex in the world, created by the U.S. government "for the increase and diffusion of knowledge." Founded on August 10, 1846, it operates as a trust instrumentality and is not formally a part of any of the three branches of the federal government. The institution is named after its founding donor, British scientist James Smithson. It was originally organized as the United States National Museum, but that name ceased to exist administratively in 1967.

A museum is an institution dedicated to displaying and/or preserving culturally significant objects. Many museums have exhibitions of these objects on public display, and some have private collections that are used by researchers and specialists. Compared to a library, a museum hosts a much wider range of objects and usually focus around a specific theme such as the arts, science, natural history, local history, and other topics. Public museums that host exhibitions and interactive demonstrations are often considered to be tourist attractions, and many museums attract large numbers of visitors from outside their host country, with the most visited museums in the world regularly attracting millions of visitors annually.