Metropolis is a city located along the Ohio River in Massac County, Illinois, United States. It has a population of 6,537 according to the 2010 United States Census. Metropolis is the county seat of Massac County and is part of the Paducah, KY-IL Micropolitan Statistical Area in Southern Illinois. History Located on the Ohio River, the Metropolis area has been settled by many different peoples throughout history. For thousands of years, varying cultures of Native Americans populated the area. The most complex society was the Mississippian culture, which reached its peak around AD 1100 and built a large city at Cahokia, near the Mississippi River and present-day Collinsville, Illinois, to the north opposite St. Louis, Missouri. Its people built large earthworks and related structures, many of which have been preserved and protected at the UNESCO World Heritage Site. Mississippian culture regional centers arose throughout the Ohio and lower Mississippian valleys, where the rivers were part of widespread trading routes used for exchange with other cultures. In 1757, Massac County was settled by a French expedition, which built Fort de L'Ascension for use during the French and Indian War against the British (the war is also known as the Seven Years' War, which took place largely in Europe). The garrison at the fort was able to resist a Cherokee attack during the war. Afterward the defeated French abandoned the fort, and many moved west of the Mississippi River to escape British rule. When the victorious British colonists arrived to take control of territory ceded by the French, the Chickasaw had already destroyed the fort. During the American Revolutionary War, the mostly ethnic French residents of the town were sympathetic to the rebels. Afterward in 1794, President George Washington ordered Fort Massac reconstructed, at a strategic site high above the Ohio River. The fort was severely damaged by the 1811–12 New Madrid earthquakes. Rather than rebuild, the US military abandoned the facility in 1814, as its forces were needed further west. Local settlers scavenged the timbers and left little behind of the original construction materials. This section of the state was largely settled by migrants from the Upper South, and many brought slaves with them. It was years after Illinois was admitted as a free state that all such slaves gained their freedom. The city of Metropolis was founded in 1839 near the site of Fort Massac by a merchant from Pittsburgh