Cliff Island could be considered the quintessential Maine Island. Cliff has deep woods, abundant wildlife, picturesque coves and some of the most beautiful beaches in the bay, all privately owned. When you stop at Cliff, you get the feeling that time has passed this place by. It lies nine miles out in Casco Bay and is the farthest - out populated island that Casco Bay Lines services. There is a small year-round population and a summer community of around 500.