Population Densities Around Martin County


Density” is always a key part of the discussion of growth in our county, but I find that many county residents—and our even elected officials—have only a hazy idea of typical population densities in towns and neighborhoods around Martin County.

They tend to underestimate the density of their own neighborhoods, both in comparison to other places and especially relative to proposed new communities.

Density—expressed as population per square mile—is the number of people living, on average, on a square mile (640 acres) of the dry land area of a given locale. It’s calculated by dividing total population by the number of square miles, unrelated to how the population is distributed over that land area.   

In starting to plan for Pineland Prairie, I examined the average densities of places all over our county and compiled the chart below.  Some of these locales are official “Census Designated Places,” and others are particular Census tracts near Pineland Prairie.

There are some surprising results from this analysis, such as the fact that Sewall’s Point and Jensen Beach, on a gross-land-area basis, have very similar population densities–1,633/sq. mi. and 1,625/sq. mi., respectively.

That’s because Sewall’s Point has a very small retail and office district, very little public open space, and is primarily residential, while Jensen Beach has a lot of retail space (where no one lives) and a lot of open space (parks and other civic spaces) to go with its denser residential neighborhoods.

All of this information is collected by the U.S. Census Bureau every 10 years, and it’s available online (at www.USA.com and other Web sites), searchable by Census tracts in every county.

Densities are all based on 2010 census data, so are probably higher today in most locales, since the land area remains the same while population grows. In the county overall, population is estimated to have grown by 8.2% (+11,965 people) between the 2010 census and 2016–from 146,318 to 158,283.

Some places had added even more people, especially the largest and most-open Census Designated Place in our county, Palm City. The land area within of the Palm City Zip code (34990) had 23,120 people in the 2010 Census, and is now estimated to have 27,680 people—an increase of almost 20% in six years.  

Ranking Martin County Places by Population Density

(Includes part of PSL in St. Lucie County, just north of C-23 Canal)
2010 Census Data, except where noted. Numbers below are people per square mile.

  1. Port Salerno: 2,803 people per square mile
  2. Martin Downs/Old Palm City: 2,767
  3. City of Stuart: 2,345
  4. North River Shores: 2,385
  5. Port St. Lucie/north of C-23 both sides of Becker Road: 2,190
  6. Hobe Sound: 2,094
  7. Sewall’s Point: 1,633
  8. Jensen Beach: 1,625
  9. Palm City (including M. Downs): 1,583
  10.  Rio: 1,028 
  11.  Indiantown: 1,013
  12.  Jupiter Island: 769
  13.  Stuart West/Cobblestone: 573

(estimated; not from Census data)