In the new movie “Shutter Island,” US marshals go to a precipitous island off the coast of Massachusetts to investigate a mystery in a huge, gothic insane asylum.
Shutter Island does not exist; there are no Shutter Islands in the entire United States, nor am I aware of any insane asylums that have ever existed on isolated American islands. There have been a number of prison or detention islands, though none quite resembled the fictional Shutter Island physically.
The last unbridged prison island in the US is McNeil Island, Washington. It houses both a large state prison complex, and a program of civil detention for sexual predators, who are essentially being confined as mentally ill.
Steep-sided, flat-topped, gloomy islands like the one in the movie are relatively rare. For physical similarity, one might go with Anacapa, in the Channel Islands of California:
(Anacapa image courtesy Scubacayman88, Flickr)
Follow on Twitter: @Worldislandinfo