Boulder is the county seat and most populous city of Boulder County and the 11th most populous city in the U.S. state of Colorado. Boulder is located at the base of the foothills of the Rocky Mountains at an elevation of 5,430 feet. The city is 25 miles northwest of Denver. Wikipedia

Orange County is a county in the U.S. state of California. As of the 2010 census, the population was 3,010,232 making it the third-most populous county in California, the sixth-most populous in the United States, and it more populous than twenty-one U.S. states. Its county seat is Santa Ana. Wikipedia