Resident Population in Mills County, TX was 4.54800 Thous. of Persons in January of 2023, according to the United States Federal Reserve. Historically, Resident Population in Mills County, TX reached a record high of 5.11700 in January of 1999 and a record low of 4.21200 in January of 1970. Trading Economics provides the current actual value, an historical data chart and related indicators for Resident Population in Mills County, TX - last updated from the United States Federal Reserve on May of 2024.