Lets make this the discussion thread for all notes here until we figure out what we are doing.

Danmer tagged this source:
https://hopkintonindependent.com/drone-photos-hopkinton-state-park-legacy-farms-north/

I found this one:
https://commons.wikimedia.org/wiki/File:Bacon_island.png

I did a lot more digging, and only source I can find is essentially Google Maps.  Some secondary sources exist, but they appear to pull it from Google.

I could not find any first party sources.  Might have to email the state park for a definitive answer.