Round Rock, Texas is 54% larger than Sunnyvale, California.
Area: 88 km2 calculated
Round Rock is a city in the state of Texas within the Greater Austin, Texas metropolitan area and Williamson County. The 2013 census estimate places the population at 109,821. Wikipedia
Area: 57 km2 calculated
Sunnyvale, officially the City of Sunnyvale, is a city located in Santa Clara County, California. As of the 2010 United States Census, the population was 140,095. The city is one of the major cities that make up the Silicon Valley located in the San Francisco Bay Area. Wikipedia