The area now known as American River was first visited by Europeans in 1802 when Matthew Flinders sailed along the north coast of Kangaroo Island. In 1803, a group of American sealers camped for four months in the area. A memorial plaque and accompanying anchor (recovered in 1969) from an early American whaling vessel is dedicated to the crew of the Union.
Frank Potts was the first official settler in 1842, before moving to the mainland and establishing the Bleasdale vineyard and winery at Langhorne Creek, John Buick, a professional boat builder, built the first house in the town in 1844. It was fashioned out of local stone, pug and sput timber and remained standing until 1985.
Somewhat erroneously, the waters of Eastern Cove, upon which the township is located, have been referred to as American River, compounding the illusion that the township is connected in any way with a river.
A fish canning factory existed for a few years from the late 1890s, remnants of which may still be found on the shore north of the town proper. Gypsum was mined at Flour Cask Bay, later at Pelican Lagoon and trucked to nearby Ballast Head, from 1956 until 1986.
Until the 1980s the town was serviced regularly by the ketches Faile, Nelcebee (last service 15 April 1982) and Ulonga, operated by R. Fricker & Co. Consequently, on cessation of this service the wharf area for some time was a redundant commercial facility, resulting in the removal of several buildings and fuel facilities. Recently however, the advent of oyster farming has seen new shedding erected and increased activity, in harmony with recreational boating activities.
The population has increased steadily in recent years, while nearby hamlets in the vicinity of Eastern Cove, such as Island Beach and Baudin Beach, have become more prominent.
Maintenance for this cache will be provided by the geocaching team Fishingmad.