Only 17 people live on that Island. Can’t find much, Lloyd Wright’s style of home...
Morris mansion was sold in 2015, a 5,300-square-foot mansion platted on 5 acres of land. The Thurston County residents who bought the home paid $1.1 million for it.
FWIW, the areas to the west and south of that island run about 300-430 feet deep, sloping up pretty quickly about a mile southwest to about 150 feet.
Thats from a color shaded relief bathymetry map of the Nisqually delta from 2001 (USGS)