[2] Double Bluff is an approximately two-mile-long public beach located on southern Whidbey Island along the shores of Admiralty Inlet, north of Puget Sound.

Fed by sand from the bluffs at its East and West ends, Useless Bay has a sandy, shallow slope; the horizontal distance between high and low tidelines can exceed 2500 feet.

The primary character of the shore here is shifting sands eroded from the bluffs with large fields of pebbles, driftwood, slabs of peat, and glacial erratic boulders.

[6] The Whidbey Formation composes the majority of the visible bluff face and consists of poorly sorted silt, clay, and sands, pebbles, and compressed slabs of peat.

Double Bluff Beach is popular with both locals and tourists because of its large size, easy access, and many activities.