Lake Carroll is a census-designated place in Carroll County, Illinois, United States, surrounding a lake of the same name. It is in northeastern Carroll County and is bordered to the north by Stephenson County. It is 10 miles northeast of Mount Carroll, the county seat, and 20 miles southwest of Freeport. Lake Carroll was first listed as a CDP prior to the 2020 census. As of the 2020 census, the population was 852.