The City of Centennial is a Home Rule Municipality located in Arapahoe County, Colorado, United States. The city population was 100,377 at the 2010 United States Census. Centennial is a part of the Denver-Aurora-Lakewood, CO Metropolitan Statistical Area. Centennial is the tenth-most populous municipality in the state of Colorado and its 2001 incorporation was the largest in U.S. history. Centennial is ranked as the 15th safest city in the country.