It has a pool of scorched oil surrounded by twelve sycamore trees in a circle.
Its location is shown on a petroglyph from the Owl Cave, which also indicates that when Saturn and Jupiter are aligned then the Grove opens to the Black Lodge.
- Real life Glastonbury is famous for being one of the most mystical sites in the world. It has connections with King Arthur (the Arthurian legend), Joseph of Arimathea, Glastonbury Tor, The Abbey, the Glastonbury Giants or Zodiac, the intersection of Ley Lines and Earth Energy Lines. Glastonbury is also believed to be the mythical place known in Arthurian Lore as 'The Isle of Avalon'.
- In the shooting scripts and The Secret History of Twin Peaks, the spelling was "Glastonbury" but Twin Peaks: An Access Guide to the Town before and the Georgia Coffee commercials used the spelling "Glastonberry". The reason for the change was never given but it has been thought that the change in spelling was provided as a reference to the pies, the notable berry pies Norma Jennings could bake at the Double R Diner.