The one of the states within the US that is not considered part of the New England group of states is Pennsylvania. Pennsylvania is in the northeast, but it is considered a mid-Atlantic state, along with New York and New Jersey. Pennsylvania, officially the Commonwealth of Pennsylvania, is a state that was founded by William Penn in the Northeastern, Great Lakes, Appalachian, and Mid-Atlantic regions of the United States. The Appalachian Mountains run through its middle. The Commonwealth is bordered by Delaware to the southeast, Maryland to the south, West Virginia to the southwest, Ohio to the west, Lake Erie and the Canadian province of Ontario to the northwest, New York to the north, and New Jersey to the east.

By area, Pennsylvania is the 33rd-largest state. It is the 5th-most populous state according to the official US Census of 2010 and the 9th-most densely populated of the 50 states. Pennsylvania's two most populous cities are Philadelphia (1,580,863), and Pittsburgh (302,407). The state capital and its 13th-largest city is Harrisburg. Pennsylvania has 140 miles (225 km) of waterfront along Lake Erie and the Delaware River. The state is one of the 13 original founding states of the United States.

Six states are considered part of the New England group of states. They are Maine, Vermont, New Hampshire, Massachusetts, Connecticut and Rhode Island. These states are grouped together for their geographic location, encompassing the north eastern corner of the USA.

More Info: en.wikipedia.org