“We’ll start with six lobster rolls,” the man in sunglasses and madras shorts said when he reached the front of the line at McLoons Lobster Shack on the tip of Sprucehead Island in Maine.

That was only his opening bid. By the time everyone in his family had weighed in, his lobster roll count was up to nine.

There are other things on the menu at McLoons — chowders and burgers and grilled littleneck clams — but the lobster roll outsells them all by far.

On the Sunday in July I spent at McLoons, in South Thomaston, Me., the place never got truly mobbed. The sky was the color of a fishing sinker and everyone knew an afternoon thunderstorm was on the way. But still they came, the locals and the visitors, almost all of them with the same thing in mind. As Mariah Watkinson, who was working the order window, put it, “There’s usually a lobster roll in every order.”