Glenstone is a private contemporary art museum in Potomac, Maryland, founded in 2006 by American billionaire Mitchell Rales and his wife, Emily Wei Rales. The museum's exhibitions are drawn from a collection of about 1,300 works from post-World War II artists around the world. It is the largest private contemporary art museum in the United States, holding more than $4.6 billion in net assets, and is noted for its setting in a broad natural landscape.