Petoskey is a city and coastal resort community in the U.S. state of Michigan. The population was 5,670 at the 2010 census. It is the county seat of Emmet County.Petoskey and the surrounding area are notable for being the setting of several of the Nick Adams stories by Ernest Hemingway, who spent his childhood summers on nearby Walloon Lake, as well as being the place where for Calliope, the protagonist of Jeffrey Eugenides' Middlesex, events take a severe and lasting turn.