Maryland is divided into two sections by Chesapeake Bay: a section to the east of Chesapeake Bay (the East Shore) and a section to the west of Chesapeake Bay (the West Shore). Although Maryland is small, it has five major land areas.
Maryland lies in an area some refer to as the Mid-Atlantic Coastal Plain. From the northeastern tip of Maryland, the plain extends south and west across Maryland almost to Washington, D.C. near the Virginia border. The plain is flat and low. Marshy areas can be found on the East Shore, including the Pocomoke Swamp. The West Shore portion of the plain has been used for farming since colonial times.
The Piedmont cuts across the state from the northeast through central Maryland in a 50-mile wide swath. The Piedmont area has low rolling landscapes and fertile valleys. The Piedmont Plateau has good farming soil except for belts of clay that are mined for brick kilns; from early colonial times, the exteriors of Maryland buildings have glowed with salmon-coloured brick made from these clay deposits. To the west and parallel to the fall line, the low Parr’s Ridge forms a drainage divide separating water flow east to the Chesapeake and southwest to the Potomac River.
To the west of the Piedmont is the Blue Ridge, a narrow, mountainous section of land near the Pennsylvania border. South Mountain and Catoctin Mountain are in the Blue Ridge Region of Maryland.
The Maryland section of the Appalachian Ridge and Valley is the northern strip of land that separates West Virginia from Pennsylvania. In the east, the Appalachian Ridge and Valley is dominated by Hagerstown Valley, which is filled with orchards and farmland.
To the west of the Blue Ridge is the Appalachian Plateau. This covers a triangle of land in the westernmost portion of Maryland. The Allegheny Mountains cover most of this area. Backbone Mountain, the highest point in Maryland, is located in this region. This area is heavily forested and contains many deep valleys, cut into the plateau by rivers.
The largest feature of Maryland’s topography is Chesapeake Bay, which serves the port of Baltimore, divides the Eastern Shore from what was once called Maryland Main, and covers around 1,840 square miles (4,770 square km). On a summer weekend as many as 100,000 boats may be seen on the water. Dredging is needed to maintain the 50-foot- (15-metre-) deep ship channel to Baltimore and to the Chesapeake and Delaware Canal, which connects the northern end of the Chesapeake to the Delaware River.
The water edges of the Coastal Plain consists of salt marshes, or wetlands which appear and disappear over time as erosion fills in a swamp or deletes an entire island. St. Clements Island (also called Blakiston Island), for example, is about one-tenth the size it was in 1634. The Chesapeake’s estuarial tributaries provide the state with about 3,200 miles (5,150 km) of shoreline.
During a storm in 1933, Assateague Island, a sand barrier island on the Atlantic shore, was divided in two. The northern portion, Fenwick Island, now contains the resort town of Ocean City. The southern portion is now Assateague Island National Seashore, which is shared with Virginia. The inlet between the two islands has allowed the creation of Ocean City’s fishing fleet.
Despite its small size, Maryland has a diverse climate. There is a continental climate in the highland west. Average temperatures in western Maryland are 65 °F (18 °C) in July and 28 °F (−2 °C) in January. The east has a humid subtropical climate, which is affected by Chesapeake Bay and the Atlantic Ocean. These large bodies of water moderate the weather but do not prevent ice formation almost every winter on the bay’s northern tributaries. In contrast, summer calms can produce high temperatures up to 107 °F (42 °C), with nearly 100 percent relative humidity. Average temperatures in eastern Maryland are 75 °F (24 °C) in July and 35 °F (2 °C) in January.
Rain levels are high enough to supply both Baltimore and Washington, D.C., with all their water. As much as 100 in (254 cm) of snow falls in western Garrett County, while 8–10 in (20–25 cm) is average for the Eastern Shore; and Baltimore receives about 22 in (56 cm). Storms sweep in from the west and south, except in late summer, when the edges of passing hurricanes often drench Maryland from the east.
The record high temperature for the state is 109°F (43°C), set on 10 July 1936 in Cumberland and Frederick counties; the record low of –40°F (–40°C), occurred on 13 January 1912 at Oakland in Garrett County.
