Kasaoka City is a port town located in the southwestern part of Okayama Prefecture, along the Seto Inland Sea. It is the central city of the Ikasa region, which includes the Kasaoka Islands, and is famous for the Kasaoka reclamation area and the breeding grounds for the horseshoe crab, a designated natural monument. In the past, the city was under direct control of the shogunate, with the shogunate magistrate's office located there. Due to the city's many hilly areas and limited flat land, large-scale land reclamation has been carried out since the Edo period. After the war, land reclamation also took place in the southeastern and southwestern parts of the city. For industry, an industrial complex is located in the Mohira district in the southwest, where manufacturing and distribution-related companies are concentrated. Furthermore, quarrying is actively carried out on Kitagishima Island, the largest of the city's islands, and the stone mined there is used in Yasukuni Shrine and Osaka Castle. Other local specialties include seafood.