Located in Yamatokoriyama City, Nara Prefecture, Koriyama Castle Ruins is the remains of a castle built by Toyotomi Hidenaga, the younger brother of Toyotomi Hideyoshi, from the Sengoku period to the Azuchi-Momoyama period. While the castle tower no longer exists, the imposing stone walls and moat still convey the castle's original appearance. The stone walls, in particular, feature numerous "repurposed stones" (tenyoseki) that were once used to house Jizo statues, stone pagodas, and stupas, evoking a sense of historical romance. Walking around the castle while admiring the stone walls is a unique way to enjoy the Koriyama Castle Ruins.

The castle has been selected as one of Japan's Top 100 Castles.

The castle ruins have been developed into a park as a place of relaxation for local residents, and visitors can enjoy leisurely strolls through the spacious grounds. In spring, approximately 800 cherry trees bloom, attracting many visitors as a famous cherry blossom viewing spot, earning it a place on Japan's Top 100 Cherry Blossom Spots. At night, the area is illuminated, creating a magical nighttime view. Additionally, in Yamatokoriyama Castle Town, located near the castle ruins, you can stroll through the historic streets and enjoy a goldfish scooping experience.