Photo: A crowded media staging area outside the Arapahoe County Justice Center in suburban Denver, where James Holmes is on trial for the 2012 movie theater shooting in which 12 were killed, 70 others wounded @CBS4Mark
Arapahoe County is one of the 64 counties in the U.S. state of Colorado. As of the 2010 census, the population was 572,003, making it the third-most populous county in Colorado. The county seat is Littleton, and the most populous city is Aurora. The county was named for the Arapaho Native American tribe who once lived in the region.
Arapahoe County is part of the Denver-Aurora-Lakewood, CO Metropolitan Statistical Area. Arapahoe County calls itself "Colorado's First County" since its origins predate the Pike's Peak Gold Rush.