As of this writing, there are 16 Smithsonian museums open in Washington. All are free of charge to explore, but two currently require timed-entry passes.
You may plan your explorations using the Smithsonian’s Virtual Visitor Center. The following Smithsonian museums in Washington, D.C., are currently open to the public:
The Archives of American Art, the National Portrait Gallery, and the Smithsonian American Art Museum are housed in the elegant Old Patent Office Building.