Port St. Lucie, Florida is 4.4 times larger than Boulder, Colorado.
Area: 68 km2 calculated
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
Area: 295 km2 calculated
Port St. Lucie is a city in St. Lucie County, Florida, United States. The population of Port St. Lucie was 164,603 at the 2010 census due to its rapid growth during the 2000s. In 2013 the State of Florida estimated the City's population at 171,016. Port St. Wikipedia