Aichi Prefecture - Wikipedia Aichi Prefecture (愛知県, Aichi-ken; Japanese pronunciation: [aꜜi tɕi, ai tɕi̥ꜜ keɴ] [2]) is a prefecture of Japan located in the Chūbu region of Honshū [3]: 11, 126 Aichi Prefecture has a population of 7,461,111 (as of 1 January 2025) and a geographic area of 5,172 92 square kilometres (1,997 28 sq mi) with a population density of 1,442 inhabitants per square kilometre (3,730 sq