Resident Population in Weld County, CO was 359.44200 Thous. of Persons in January of 2023, according to the United States Federal Reserve. Historically, Resident Population in Weld County, CO reached a record high of 359.44200 in January of 2023 and a record low of 89.29700 in January of 1970. Trading Economics provides the current actual value, an historical data chart and related indicators for Resident Population in Weld County, CO - last updated from the United States Federal Reserve on May of 2024.