Resident Population in Big Horn County, MT was 12.79600 Thous. of Persons in January of 2024, according to the United States Federal Reserve. Historically, Resident Population in Big Horn County, MT reached a record high of 13.45400 in January of 2017 and a record low of 10.05700 in January of 1970. Trading Economics provides the current actual value, an historical data chart and related indicators for Resident Population in Big Horn County, MT - last updated from the United States Federal Reserve on April of 2026.