Morioka Castle occupies a long and narrow elliptically-shape hill approximately 300 meter long by 100 meter wide. The southeastern side faces the Nakatsu River, and formerly the main stream of Kitakami River protected the western side. As white granite was readily available in the vicinity, most of the ramparts were faced in stone, which was unusual for castles in the Tōhoku region at the time. Both the Toyotomi and Tokugawa governments encouraged the Nanbu to build a strong fortification, partly as a counter to the strength of the Date clan to the south.