The Delaware Valley, sometimes referred to as Greater Philadelphia, Philadelphia metropolitan area, or Philadelphia tri-state area, is a major metropolitan and tri-state region in Northeast United States that centers on Philadelphia, the 6th-most populous city in the United States, and spans part of three states: Southeastern Pennsylvania, Southern New Jerse…The Delaware Valley, sometimes referred to as Greater Philadelphia, Philadelphia metropolitan area, or Philadelphia tri-state area, is a major metropolitan and tri-state region in Northeast United States that centers on Philadelphia, the 6th-most populous city in the United States, and spans part of three states: Southeastern Pennsylvania, Southern New Jersey, and Northern Delaware. With a core of metropolitan statistical area population of 6.288 million residents, while the combined statistical area population of 7.366 million, Delaware Valley is the eighth-largest metropolitan region in the United States and the 68th-largest metropolitan region in the world.