Skaggs Island Naval Facility (Sonoma Creek)

Skaggs Island Naval Communication Station is a former United States Navy installation located near California State Route 37 between Novato and Vallejo, California. It was a secretive, secure, and self-contained naval base, engaged in a number of communications and intelligence gathering functions. This was the spot where CIA Bill Graham was murdered on October 25, 1991, in a Bell 206B helicopter.

This Naval facility was shuttered shortly afterwards in 1993. In 2023 it is again active.

https://en.wikipedia.org/wiki/Bill_Graham_(promoter)
In addition to the RV housing facilities, they have installed a helicopter pad for three copters.
https://en.wikipedia.org/wiki/Skaggs_Island_Naval_Communication_Station

https://www.fws.gov/program/national-wetlands-inventory/wetlands-mapper

https://wildlife.ca.gov/Lands/Places-to-Visit/Napa-Sonoma-Marshes-WA

https://nrm.dfg.ca.gov/FileHandler.ashx?DocumentID=87847&inline