The City of Northglenn is a home rule municipality located in Adams and Weld counties, Colorado, United States. Northglenn is a part of the D…The City of Northglenn is a home rule municipality located in Adams and Weld counties, Colorado, United States. Northglenn is a part of the Denver–Aurora–Lakewood, CO Metropolitan Statistical Area. As of the 2020 census the city's population was 38,131. It was built as a master planned community in 1959 by Jordon Perlmutter.