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Was organized as a town in 1833, and became a city in 1837. In the latter part of the seventeenth century, the French built a fort on the site of the present city, and later the United States Government erected a fort (Fort Dearborn) which was not abandoned until 1837. In October, 1871, Chicago was visited by the most disastrous fire of modern times. Chicago University was opened here in 1892, and here in 1893 the Columbian Exposition was held. The population of Chicago was in 1840, 4479; 1850, 29,963; 1860, 109,206; 1870, 306,605; 1880, 503,185; 1890, 1,099,880.