Palos Hills is a city in Cook County, Illinois, United States. It is a southwest suburb of Chicago. The city was established in 1958 and had reacheā¦Palos Hills is a city in Cook County, Illinois, United States. It is a southwest suburb of Chicago. The city was established in 1958 and had reached a population of 18,530 in the 2020 census. It is named after Palos de la Frontera, Spain, from which Christopher Columbus set sail to North America. Moraine Valley Community College as and Amos Alonzo Stagg High School are its main schools.