Well, in many American fiction works, the beach house could be found in places like Florida's coast, or in a fictional beach town in New England. The choice of location often ties into the themes and plot of the story.
It varies depending on the specific piece of fiction. Sometimes it's on the east coast, other times it could be on the west.
The location of the beach house in American fiction can be anywhere. It might be in a fictional town along the Gulf of Mexico or a made-up beach community in California. It all depends on the author's imagination and the story's setting.