Resident Population in Garfield County, MT was 1.21100 Thous. of Persons in January of 2023, according to the United States Federal Reserve. Historically, Resident Population in Garfield County, MT reached a record high of 1.80000 in January of 1971 and a record low of 1.16100 in January of 2008. Trading Economics provides the current actual value, an historical data chart and related indicators for Resident Population in Garfield County, MT - last updated from the United States Federal Reserve on May of 2024.