The Appalachian Mountains are to the east what the Rocky Mountains are to the west. In Maryland, this chain of mountains covers the western part of the state, and makes up one-fifth of its landmass. Mountains including the Blue Ridge, Allegheny, Green Ridge, Meadow, Negro, and Sugar Loaf divide the area up into valleys.

In total, the Appalachians stretch from Newfoundland, Canada down to Alabama in the southern U.S. The Appalachian Trail extends 2,167 miles running from Mount Katahdin in Maine to Springer Mountain in Georgia. In Maryland the trail runs for 41 miles, from the Maryland/Virginia border through South Mountain State Park to Washington Monument State Park and is steeped in Civil War history.

There are a number of outdoor activities associated in and around the Appalachian ranges in Maryland, from hiking and cycling the trails to swimming and boating in Deep Creek, which is surrounded by the mountains.