The Lehigh Valley, known officially by the United States Census Bureau and the United States Office of Management and Budget as the Allentown-Bethlehem-Easton, PA-NJ Metropolitan Statistical Area and referred to colloquially as The Valley is a metropolitan region officially consisting of Carbon, Lehigh and Northampton counties in eastern Pennsylvania and Warren county on the western edge of New Jersey, in the United States.The Lehigh Valley's largest city, with a population of 119,104, is Allentown.The Lehigh Valley is the fastest growing and third most populous region in the state of Pennsylvania with a population of 821,623 residents as of the 2010 U.S. Census. It is eclipsed in total population only by the metropolitan areas of Philadelphia and Pittsburgh in Pennsylvania. It is the 64th most populated metropolitan area in the United States. Lehigh County, the Valley's largest county in terms of overall population, is among the fastest growing in the nation as well, ranking in the 79th percentile for population growth between 2010-2012. The core population centers are located in southern and central Lehigh and Northampton counties along U.S. Route 22 and Interstate 78.In March 2014, the Lehigh Valley was recognized by business publication Site Selection Magazine as being the second-best performing region of its size for economic development in the entire United States. It was also ranked by Fortune in May 2015 as being among the top 10 best places in the U.S. to locate corporate Finance and Information Technology operations for companies, such as call centers and IT support.