The remains of Naganuma Castle stand in Naganuma, Sukagawa, in Fukushima Prefecture. There are several versions of the origins of the castle: some say it was built by Naganuma Ryuji on Hidakami Mountain in 1260, or that it was built by the Naganuma family during the Nanbokucho Period, but the truth is still unknown.

Various families contributed to the improvement and extension of the castle: the Niikuni family of the Eiroku Era, and the Gamo family after the Oshu Shioki, or the Uesugi family. Naganuma Castle was completed as a potent defensive base in medieval times.

After the Battle of Sekigahara in 1600, Aizu became Gamo territory once again, which resulted in the Gamo family taking control of Naganuma Castle as well. However, due to the Ikokuichijorei (a decree stating that there can only be one castle in one country) in 1615, the Naganuma Castle was dismantled.

Since the Meiji period, activities such as tree-planting, which is a symbol of Naganuma-machi, have been carried out, transforming the area into a place of relaxation loved by the town's people. Currently, the old castle site has also been designated as an historic spot of Sukagawa. Naganuma Castle is a place adored and revered by the people of Naganuma even today.