Calumet City is a city in Cook County, Illinois, United States. The population was 37,042 at the 2010 census, a decline of 5.2% from 2000. The ZIP code is 60409.Calumet City was founded in 1893 when the villages of Schrumville and Sobieski Park merged under the name of West Hammond, since it lies on the west side of the Illinois-Indiana line from Hammond, Indiana. In 1924, West Hammond officially became Calumet City after its citizens voted to change the name in 1923.In addition to being bordered to the east by Hammond, it is also bordered by Burnham and Chicago to the north, Lansing to the south, and South Holland and Dolton to the west.