Kanagawa Prefecture (神奈川県, Kanagawa-ken) is a prefecture located in southern Kantō region of Japan. The capital of the prefecture is Yokohama. Kanagawa is part of the Greater Tokyo Area. The prefecture has some archaeological sites going back to the Jōmon period (around 400 BCE). About 3,000 years ago, Mount Hakone produced a volcanic explosion which resulted in Lake Ashi on the western area of the prefecture.