Denver County, CO - Resident Population in Denver County/city, CO was 729.01900 Thous. of Persons in January of 2024, according to the United States Federal Reserve. Historically, Denver County, CO - Resident Population in Denver County/city, CO reached a record high of 729.01900 in January of 2024 and a record low of 468.13900 in January of 1990. Trading Economics provides the current actual value, an historical data chart and related indicators for Denver County, CO - Resident Population in Denver County/city, CO - last updated from the United States Federal Reserve on April of 2026.