Nagashino Castle was a Sengoku period Japanese castle located in what is now Shinshiro, eastern Aichi Prefecture, Japan. It is noteworthy as the site of the crucial Battle of Nagashino between the combined forces of Tokugawa Ieyasu and Oda Nobunaga against Takeda Katsuyori in 1575. The ruins have been protected as a National Historic Site since 1929, the first time a former castle site had received such protection.

Shinshiro is a city located in Aichi Prefecture, Japan. As of 1 October 2019, the city had an estimated population of 44,581 in 17,691 households, and a population density of 89.3 persons per km2. The total area of the city is 499.23 square kilometres (192.75 sq mi).