Arvada is a home rule municipality on the border between Jefferson and Adams counties, Colorado, United States. The city population was 12…Arvada is a home rule municipality on the border between Jefferson and Adams counties, Colorado, United States. The city population was 124,402 at the 2020 United States Census, with 121,510 residing in Jefferson County and 2,892 in Adams County. Arvada is the seventh most populous city in Colorado. The city is a part of the Denver–Aurora–Lakewood, CO Metropolitan Statistical Area and the Front Range Urban Corridor. The Olde Town Arvada historic district is 7 miles northwest of the Colorado State Capitol in Denver.