Port St. Lucie is a city in St. Lucie County, Florida, United States. It is the most populous municipality in the county with a population of 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. Lucie forms part of a metropolitan area called the Port St. Lucie, Florida Metropolitan Statistical Area that in 2013 was estimated to have 438,095 residents. As of 2015, the city had 179,413 residents, surpassing Fort Lauderdale in population.