The state of Pennsylvania is one of the states of the United States of America and is situated in the Middle Atlantic as well as the North Eastern region of the country. The official name of the state is the Commonwealth of Pennsylvania, and is known colloquially to Northeasterners and natives by the abbreviation of the name, PA.

The state of Pennsylvania has been given the moniker the Keystone State since the year 1802. This nickname refers to both the location of the state, as well as the economy. The location is a keystone because of the fact that it is situated in the central part of the Thirteen Colonies. These colonies were the initial colonies which formed the United States of America. With respect to the economy, the state is a keystone since there area number of industries working here, such as the manufacturing industry in the North, which makes products such as the Conestoga wagons, and the agricultural industry in the South, which makes products such as tobacco, fiber, feed, and food.

Another nickname which has been given to the state of Pennsylvania is the Quaker State. In the times of the colonies, the official name of the state was the Quaker Province. The largest city of the state is the city of Philadelphia. There is an important sea port on the Delaware River, as well as a number of shipyards. Pennsylvania is surrounded by New York, New Jersey, Delaware and Maryland, West Virginia, and Ohio on the north, east, south east, south west, and west respectively.

There are varying climates which are produced in the state as a result of its varied geography. The climate in the south eastern part of the state is warmer as compared to the other parts. The climate in Greater Pennsylvania can be classified as being a humid continental climate. Humid subtropical climate also prevails in Maryland and Delaware which are situated in the south.