The Bureau of the Census has reported that the city of Chicago lost more than 200,000 people between 2000 and 2010. At 2,696,000, this takes Chicago to its lowest population since 1910, and nearly 1,000,000 fewer than its census population peak of 3,621,000 in 1950. In 1910, the city had a population of 2,185,000, and increased in 1920 to 2,702,000.
The Bureau of the Census had estimated Chicago’s population at 2,851,000 in 2009, down from the 2000 census count of 2,897,000. Chicago is the seat of Cook County, which lost 180,000 between 2000 and 2010, though outside the city of Chicago, Cook County gained approximately 20,000 residents.