Lets get started with the auto license in Colorado. City of Aurora is a Home Rule Municipality covers the counties of Arapahoe, and Douglas Adams in Colorado. Aurora is an eastern suburb of Denver-Aurora-Boulder, CO Metropolitan Statistical Area (Metro Denver). The city is the third most populous city in Colorado and the 56th most populous city in the United States. The city had a population of 325,078 in 2010 census. Denver and Aurora are the major cities in the metropolitan Denver area in 2007 had an estimated population of 2,464,866. (22nd most populous MSA) But Denver and Aurora are less than half the population of Metro Denver and Aurora area about half the population of Denver. The estimated population of metropolitan Denver in 2007 was 2,998,878 (15th most populous CSA).