During the Edo period of Japanese history, a jin'ya (陣屋) was the administrative headquarters of a small domain or parcel of land held by the Tokugawa shogunate, as well as the residence of the head of the administration, and the associated grain storehouse. While larger domains had castles, certain smaller domains did not, and the jin'ya, much smaller than a castle, housed the administration. Some, such as the Komono Jin'ya in Komono, Mie Prefecture, had a watchtower (yagura), mimicking the donjon of a castle. Others had moats or earthen walls, in some cases left over from an earlier castle on the site.
Generally, domains assessed at 30,000 koku or less had a jin'ya instead of a castle. Additionally, they were found on shogunal lands and those headed by hatamoto, and within large domains jin'ya served as district headquarters (gun daikan-sho). They were also found in exclaves of domains.
The "three great jin'ya" were at the Iino, Tokuyama and Tsuruga Domains.