;) Surely you are talking about the Donner party [1] cannibalism incident. Coincidentally, the film The Road, which also featured cannibalism, had a short scene filmed at one of the tunnels on the closed Pennsylvania Turnpike [2].

[1] https://en.wikipedia.org/wiki/Donner_Party

[2] https://en.wikipedia.org/wiki/The_Road_(2009_film)