Ichabod references Roanoke Island (NC), the "Lost Colony" . This is an actual place, and the history he tells is based in truth. There was an actual John White who led the colony in 1587, left for supplies, and returned to find it abandoned three years later. What is not revealed in the show is that the colony was actually established a few years earlier, and involved complex relations with two native groups (the Croatoan and the Roanoke). The leader of the Roanoke came to believe his people should resist colonization. The resulting tensions may have contributed to the disappearance of the colonists.
At 14:20 we see a sign for The Rockefeller State Park Preserve/Witch's Spring Trail. This is the sign posted at the actual entrance to the park in today's Sleepy Hollow.