No one quite knows where this charcoal was done, only that no building resembling it ever existed on Sand Island, Oahu, Hawaii. There is a Sand Island in upstate Michigan, where Jack is known to have spent time. Structures exist there from this period in history. At the same time, some people think it resembles a fishing shack, perhaps from Block Island, Rhode Island, or even from Vermont.
Then, too, it resembles a New England farmhouse, and there were and still are many in upstate New York, where Jack painted. The photograph used in the banner of his estate auction in 2007 shows him sitting on a highway barrier and sketching a structure sited in the valley below. No doubt, he was in upstate New York when he drew it.
The video cited below shows a restored 1665 Pilgrim farmhouse in Massachusetts. Like Jack's structure, it comprises the main house, a center kitchen, and a carriage house, formerly a barn. A newer barn stands across the driveway from the house. The style of connecting barns to houses came about to allow farmers to move between home and work without venturing outside, into the bitter cold of New England winters.