Hei District was one of the four modern districts created in former
Awa Province on April 1, 1889. Much of the area of the district was formerly under the control of various minor
feudal domains of former
Nagao Domain (38 villages),
Nishio Domain (11 villages),
Awa-Katsuyama Domain (9 villages), shared between Awa-Katsuyama and Nagao (13 villages) and under direct central government control (4 villages). At the time of its modern creation, the district consisted of eleven villages. The town of Nago was proclaimed in 1893, Katsuyama in 1896 and Hota in 1897. On April 1, 1897 Hei District was merged into
Awa District, Chiba. The area of former Hei District covered all of modern
Kyonan and portions of
Tateyama and
Minamibōsō.