The Chesapeake Bay (/ˈtʃɛsəpiːk/ CHESS-ə-peek) is an estuary lying inland from the Atlantic Ocean, and surrounded by the North American mainland to the West, and the Delmarva Peninsula to the East. It is the largest such body in the US. The northern bay is within Maryland, the southern portion within Virginia, and is a very important feature for the ecology and economy of those two states, as well as others.