Open daily 10 a.m. to 5:30 p.m.
Admission is always free!
2 Massachusetts Ave., N.E.
Washington, DC 20002
The museum's main entrance is located on the corner of First Street and Massachusetts Avenue NE. Other entrances have variable hours.
This upside-down blue plane within a red frame is the most famous U.S. stamp and one of the world’s most famous printing errors. Only one misprinted sheet of 100 stamps was sold.