Whidbey Isl. History - FORTS
Was stationed at NAS Whidbey in the 70's, used to run around Fort Casey. Ran into a group that was exploring the tunnels under the fort. They were looking for the connecting tunnels to the other Puget Sound forts in the area.
see map
Don't know the out come of their adventure. Would be good to know now though.
Links to sites for more info:
https://www.northamericanforts.com/West/Washington/Puget_Sound/
https://www.fortwiki.com/Fort_Worden
https://coastartillery.org/ (no http(s):// needed)
WWG1WGA