For the city in Russia , see Saint Petersburg St. Petersburg ( shortened to St. Pete by the area residents ) is a city in the U.S. state of Florida . St. Petersburg ( often shortened to St. Pete ) is a city in Pinellas County , Florida , United States long known as a vacation destination for both American and foreign tourists . As of 2008 , the population estimate by the U.S. Census Bureau is 245,314 , making St. Petersburg the fourth largest city in the state of Florida and the largest city in Florida that is not a county seat .