The City of Arvada is a city in Jefferson County Colorado, USA. It is a suburb of Denver. The United States Census Bureau estimated the city population at 111,707 residents in 2013. Arvada is the seventh largest city in Colorado. The Olde Town Arvada historic district is located northwest of the Colorado State Capitol in Denver. In 1850 gold was discovered in Arvada. It was the first gold discovery in Colorado. News of the discovery set off a gold rush.