Resident Population in Union County, NM was 3.92600 Thous. of Persons in January of 2024, according to the United States Federal Reserve. Historically, Resident Population in Union County, NM reached a record high of 5.21900 in January of 1982 and a record low of 3.70700 in January of 2006. Trading Economics provides the current actual value, an historical data chart and related indicators for Resident Population in Union County, NM - last updated from the United States Federal Reserve on April of 2026.