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 the home of Moraine Valley Community College as well as Amos Alonzo Stagg High School.