>Planefags - this base map layer is really interesting. Notice the no fly are just to the south due to NatSec reasons? I had no idea!
The magenta FOR REASONS OF NATIONAL SECURITY pilots are requested to avoid flight at and below 2900' MSL in this area is Naval Magazine Indian Island where they service Ohio Class SSBN & SSGN subs
https://www.cnic.navy.mil/regions/cnrnw/installations/naval_magazine_indian_island.html