Westminster is a Home Rule Municipality in the U.S. state of Colorado, in Adams and Jefferson counties. Westminster is a Denver suburb to the northwest. The Civic Center in Westminster is located 9 miles northwest of Colorado State Capitol. The population is estimated at more than 113,000. Westminster is Colorado's 7th most populous city. Westminster has a total area of 34 square miles. Several state highways cross Westminster: I-25, US 36, US 287, SH 95, SH 121, and SH 128. Westminster is serviced by Denver International Airport and neighboring Metropolitan Rocky Mountain Airport.