Resident Population in Phillips County, CO was 4.47600 Thous. of Persons in January of 2023, according to the United States Federal Reserve. Historically, Resident Population in Phillips County, CO reached a record high of 4.67100 in January of 1983 and a record low of 3.90000 in January of 1971. Trading Economics provides the current actual value, an historical data chart and related indicators for Resident Population in Phillips County, CO - last updated from the United States Federal Reserve on May of 2024.