Residents voted to incorporate the City of Centennial on September 12, 2000 and elected its first officials on February 6, 2001. Centennial officially became a city on February 7, 2001. The quest for a new city took almost two and half years. The campaign included victories in the state legislature and state Supreme Court. Formation of the new city was approved by a 77 percent margin in the incorporation election. It was the largest city incorporation in U.S. history