The Briar Patch is a location that is exposed during the Rescuing Roosevelt quest.
The first time you enter the Briar Patch, you will need 15 Fireflies, but after that, you can enter and leave the Briar Patch whenever you wish.
The Briar Patch first appeared in the game on 6th October 2011, and was the first 'location' object.
Inside the Briar PatchEdit
After entering the Briar Patch, you are transported to a new location. In appearance, it is like a new, untouched town with no buildings, and only debris on the ground.
After completing the quest, Growing Up, you will no longer be able to enter the Briar Patch, getting the message:
You already rescued Roosevelt, there's nothing else in the briar. Buy machetes to explore your town?
The briar remains inaccessible from this point on.