Perhaps you are referring to recorded plats and/or the recorded neighborhood plan and overlay.
For us regular folk, Grayton Beach stretches from the eastern edge of Grayton Beach State Park (bordering WaterColor) to the eastern shore of Little Redfish Lake. Grayton Preserve subdivision just beyond that is in Blue Mountain Beach, although residents and rental owners of that subdivision might argue that.
Lakeplace is definitely Grayton, even though gated communities are anti-Grayton.
As far as the northern boundary of Grayton, might as well call it Grayton Village Rd. And of course the southern boundary is the Gulf of Mexico.