Baltimore ( /ˈbɒltɨmɔr/, colloquially /ˈbɔl.mɔr/) is the largest city in the U.S. state of Maryland. It is located in the central area of the state along the tidal portion of the Patapsco River, an arm of the Chesapeake Bay. The independent city is often referred to as Baltimore City to distinguish it from surrounding Baltimore County. Founded in 1729, Baltimore is the largest seaport in the Mid-Atlantic United States and is situated closer to Midwestern markets than any other major seaport on the East Coast. Baltimore's Inner Harbor was once the second leading port of entry for immigrants to the United States and a major manufacturing center. After a decline in manufacturing, Baltimore shifted to a service-oriented economy.