Château de Fukuyo, Medieval fortress in Nagano Prefecture, Japan

Fukuyo Castle is a Sengoku-period mountain castle site in Minowa, Nagano Prefecture, also known as Minowa Castle. It was held by Fujisawa Yorichika and fell to Takeda Shingen's forces in 1545; in 1582 Yorichika retook it but lost it again to Hoshina Masanao. The grounds were designated a Nagano Prefecture historic site on 3 July 1969.

The fortress came into being as a military stronghold during the Sengoku period, when regional lords built fortifications to protect their territories against rival clans. It mirrors the defense strategies of that turbulent era in Japanese history.

The castle is also called Minowa Castle, though a separate Minowa Castle exists in the same town; some scholars argue the "Minowa Castle" in historical records is this site. Another Fukuyo Castle stands in Matsukawa, Shimoina District, also a designated historic site.

Fukuyo Castle lies in Minowa, Nagano Prefecture, and is a prefectural historic site; the ruins are reached on foot, so allow time for walking and wear shoes suited to uneven ground. The site is a designated historic site rather than a staffed facility, so bring water and check the weather before setting out.

The castle is also called Minowa Castle, and some historians argue that Edo-period documents referring to "Minowa Castle" actually describe this site rather than the nearby castle of the same name. A second, unrelated Fukuyo Castle exists in Matsukawa, Nagano Prefecture.