Resident Population in St. Croix County, WI was 96.76300 Thous. of Persons in January of 2023, according to the United States Federal Reserve. Historically, Resident Population in St. Croix County, WI reached a record high of 96.76300 in January of 2023 and a record low of 34.35400 in January of 1970. Trading Economics provides the current actual value, an historical data chart and related indicators for Resident Population in St. Croix County, WI - last updated from the United States Federal Reserve on May of 2024.