In the Memorial's fourth floor is The George Washington Museum. It was built and is maintained through the generosity of the Northern and Southern Masonic Jurisdictions of the Scottish Rite of Freemasonry. Initially completed in 1966 it was most recently renovated in 2003 and presents a rich variety of Washington relics, paintings, prints, and historical documents.

The main floor examines George Washington according to the several roles and offices he filled in his life: planter, soldier, and president. In a commanding position is an impressive bronze statue of Washington. It is the work of Donald DeLue and was originally commissioned in 1959 for the Grand Lodge of Louisiana. Among the many intriguing artifacts are items from the Washington family, including a Bible, a field trunk used by Washington during the War for Independence and flag from Washington's body guards. Also displayed are items from Washington's participation in the cornerstone ceremony of the U.S. Capitol. Lastly on display is a watch used by Dr. Elisha Cullen Dick at Washington death and two military sabers. The sabers were placed on Washington's coffin during his funeral. On the upper level are more displays related to the construction of the Memorial, Masonic history and image and objects from Mount Vernon and the Washington Family.