Under the Dome by Stephen King

Under the Dome is the story of the small town of Chester's Mill, Maine which is inexplicably and suddenly sealed off from the rest of the world by an invisible force field. No one can get in and no one can get out.

When food, electricity and water run short, the normal rules of society are changed. A new and more sinister social order develops, Dale Barbara, a young Iraq veteran, teams up with a handful of intrepid citizens to fight against the corruption that is sweeping through the town and to try to discover the source of the Dome before it is too late...