Brookfield, village, Cook county, northeastern Illinois, U.S. Located on Salt Creek, it is a residential suburb of Chicago, located about 12 miles (20 km) west of downtown. Settlement of the area began in 1888–89, when Samuel Eberly Gross, a land promoter originally from Pennsylvania, began offering lots for sale. Initially called Grossdale, the village was renamed in 1905. Its major attraction is the Chicago Zoological Park, popularly known as Brookfield Zoo (opened 1934). Inc. 1893. Pop. (2000) 19,085; (2010) 18,978.