According to this:
http://www.dep.state.fl.us/lands/FFAnnual/B_South_Walton%20County.pdf
http://graytonbeach.com/ecotourism.html
Approximately 40% of Beaches of South Walton's 56,000 acres is owned by the State of Florida and thus is protected from future development. That's 25,000 acres.
http://www.secinfo.com/d13ACs.15yn.d.htm
JOE is Florida's largest private landowner. As of March 31, 2004,
JOE owned approximately 830,000 acres, concentrated primarily in
Northwest Florida. These holdings included approximately 355,000 acres
within 10 miles of the coast of the Gulf of Mexico.
"This land analysis represents an important part of our value
creation process," said Peter S. Rummell, chairman and CEO of JOE.
"Only through an increasingly detailed understanding of our land are
we able to develop strategies to move it to a higher and better use
over time."
"When this management team arrived at JOE in 1997, we were
entrusted with more than 1,000,000 acres then being used primarily as
timberland," said Rummell. "We have demonstrated our capability to
identify higher and better uses and to make these uses a reality. Of
the lands held in 1997, we have sold, developed or identified a
potential higher and better use for approximately 800,000 acres, or
about 80 percent."
"In this most recent analysis, we were able to identify tens of
thousands of acres of what was once considered timberland as suitable
to support a wide range of residential, commercial, recreational and
conservation uses," said Rummell. "We will continue to work to
identify improved uses for a substantial portion of our remaining
timberland acres."