It contains the largest known shell midden in western Japan, and was designated a National Historic Site in 2008.

The middens associated with such settlements contain bone, botanical material, mollusc shells, sherds, lithics, and other artifacts and ecofacts associated with the now-vanished inhabitants, and these features, provide a useful source into the diets and habits of Jōmon society.

The Hikozaki Shell Mound is located on the south coast of former Kojima Bay facing the Seto Inland Sea.

Acorn underground storage pits have also been found in the swampy area at the tip of the hill.

[2] The site is located about five minutes on foot from Hikosaki Station on the JR West Uno Line.