Deer Park is a village in Lake and Cook Counties, Illinois. Per the 2020 census, the population was 3,681. The village is one of the few left in the Chicago area that enjoy a green belt which is bordered by two large natural areas providing outdoor recreation and open space. The village is home to popular shopping and dining destinations: Deer Park Town …Deer Park is a village in Lake and Cook Counties, Illinois. Per the 2020 census, the population was 3,681. The village is one of the few left in the Chicago area that enjoy a green belt which is bordered by two large natural areas providing outdoor recreation and open space. The village is home to popular shopping and dining destinations: Deer Park Town Center and the Town Center Promenade. The town is also home to the Vehe Farm, an Illinois Centennial Farm.