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. It is located 125 miles (201 km) southeast of Orlando. In 2019, the United States Census Bureau estimated the city's population at 201,846. The Port St. Lucie Metropolitan Area includes the counties of St. Lucie County & Martin County and as of 2016 had an estimated population of 465,208. Port St.