Maruoka Domain was a feudal domain under the Tokugawa shogunate of Edo period Japan. It was based at Maruoka Castle in eastern Echizen Province in what is now the Maruoka neighbourhood of modern-day Sakai, Fukui. It was ruled during its history by the Honda clan, and subsequently by the Arima clan.

Maruoka Castle is a hirayama-style Japanese castle located in the Maruoka neighbourhood of the city of Sakai, Fukui Prefecture, in the Hokuriku region of Japan. It also called Kasumi-ga-jō due to the legend that whenever an enemy approaches the castle, a thick mist appears and hides it. Built at the end of the Sengoku period, the castle was occupied by a succession of daimyō of Maruoka Domain under the Edo period Tokugawa shogunate. The site is now a public park noted for its sakura. The castle's relatively small tenshu claims to be the oldest in the country, a claim which is challenged by both Inuyama Castle and Matsumoto Castle.