Nepean Bay lies between
Point Marsden and
Kangaroo Head on the north-east coast of Kangaroo Island facing into
Investigator Strait. Nepean Bay itself includes the following
coastal inlets from west to east - Bay of Shoals, Western Cove and Eastern Cove. Eastern Cove itself includes an inlet consisting of a channel known as American River and a lagoon system known as
Pelican Lagoon.
Bay of Shoals The Bay of Shoals is a body of water which is located immediately north of the settlement of
Kingscote and whose mouth is located between Cape Rouge in the north and Beatrice Point in the south over a distance of about . The bay has a maximum charted depth of . Its mouth is bounded by a
spit known as 'The Spit' which extends from Cape Rouge to within of Beatrice Point, includes the islets of
Busby and
Beatrice and is reported as being exposed during local tides, i.e. ‘drying.’ Access for watercraft into the bay is via a natural channel at its southern end near Beatrice Point.
Western Cove Western Cove is a body of water whose mouth is located between Beare Point in the west and Morrison Point in the east separated by a distance of about . The cove has a maximum depth of about at its mouth. Its shoreline is described as (distances in nautical miles):The shore of Eastern Cove, between Kangaroo Head and
American Beach, 2.5 miles S(outh), is rugged and rocky. Between the SW end of American Beach and Rocky Point, it consists of alternate beaches and low, rocky points. A sandy beach forms the S(outh) shore between Rocky Point and Strawbridge Point, 2.75 miles WNW. The S(outh) side of the cove is low with wooded hills at the back. Eastern Cove includes
Ballast Head Harbor on the western side near
Ballast Head. ==European discovery==