The museum's atrium features vehicles used to deliver mail throughout the history of the USPS, including planes, trains and automobiles.[4] Historical exhibits guide visitors through the postal service's inception and expansion, as well as its role in significant national events such as World War II.[5][6] "Systems at Work" explores historic and current technologies involved in mail processing and delivery, such as message boxes, ZIP codes, optical scanners and conveyor systems.[7]
The museum holds the National Philatelic Collection. The museum has a gift shop and a United States Postal Service philatelic sales window. Admission is free.
In 2005, the museum acquired the childhood stamp collection of the late singer/songwriter John Lennon.[8] From June 2015 until December 2019, the museum displayed the 1856 British Guiana 1c magenta, the world's most valuable stamp, which sold for nearly $10 million.[9]
In September 2009, the museum received an $8 million gift from investment firm founder William H. Gross to help finance an expansion project. The William H. Gross Stamp Gallery of the museum is named in his honor.[10]