Tucson, Arizona is 8 times larger than Orange, California.
Area: 73 km2 calculated
The city of Orange is located in Orange County, California. It is approximately 3 miles north of the county seat, Santa Ana. Orange is unusual in that many of the homes in its Old Town District were built prior to 1920. Wikipedia
Area: 590 km2 calculated
Tucson is a city in and the county seat of Pima County, Arizona, United States, and home to the University of Arizona. The 2010 United States Census puts the city's population at 520,116, while the 2013 estimated population of the entire Tucson metropolitan area was 996,544. Wikipedia