Port St. John is a census-designated place located in the U.S. state of Florida. It is within Brevard County part of the Palm Bay-Melbourne-Titusville Metro Statistical Area. It has a total area of 3.8 square miles at 28°28′37″N 80°47′19″W. The elevation is 26 feet above sea level. As of the 2010 census data, it had a total population of 12,267. The population density was 3,200/sq mi. Estimated per capita income in 2016 was $24,532. Recent job growth is positively increased by 0.86 percent. The average travel time is 19 minutes. It has Zip code 32927.