Ono Island is a 5.5-mile (8.9 km) long barrier island in southern Baldwin County, Alabama, at the mouth of Perdido Bay on the northern Gulf of Mexico. It is bordered by Bayou St. John to the north and Old River to the south. Surrounding communities include Perdido Key, Florida to the south and east and Orange Beach, Alabama to the west.
The island is home to a single community which is not within the corporate limits of any municipality. It is both private and gated. Although not within any municipality the island is subject to governance by the Baldwin County Commission. Emergency services are provided by nearby communities. The island is accessed via a private, guarded, bridge from State Route 182.