* Largest estuary in the United States
* Forms the western border of Maryland
* Provides a natural harbor for ships
* Home to a variety of marine life, including fish, shellfish, and crabs
Atlantic Ocean:
* Forms the eastern border of Maryland
* Provides a source of food and trade
* Home to a variety of marine life, including fish, whales, and dolphins
Potomac River:
* Forms the southern border of Maryland
* Flows into the Chesapeake Bay
* Provides a source of transportation and trade
* Home to a variety of fish and wildlife
Appalachian Mountains:
* Form the western border of Maryland
* Provide a natural barrier to westward expansion
* Home to a variety of forests, wildlife, and mineral resources
Piedmont Plateau:
* Lies between the Appalachian Mountains and the Atlantic Ocean
* Consists of rolling hills and valleys
* Home to a variety of forests, farms, and orchards
Coastal Plain:
* Lies along the Atlantic Ocean
* Consists of flat, low-lying land
* Home to a variety of marshes, swamps, and barrier islands