The castle was originally built during the Sengoku period by the Naito clan to serve as a defensive stronghold.
Archaeological excavations revealed that the castle utilized 'horikiri' (trench) fortifications to isolate mountain ridges.
The castle served as an important location for the Later Hojo clan before falling in 1590.
The park contains a wide variety of flora, including approximately 500 cherry trees that bloom between late March and early April.
Some sections of the park feature reconstructed signage detailing the castle's historical layout and its role in the Kanto region's military history.
Tsukuiko Shiroyama Park is built on the ruins of the 16th-century Tsukui Castle, a strategic mountain fortress that once commanded the surrounding Sagami River valley. The park features the remains of earthen ramparts, moats, and stone walls integrated into a hilly terrain covered in dense forest. Visitors can access the Tsukui-shiroyama Shrine located within the park grounds. The park is highly regarded for its spring cherry blossoms and autumn foliage. Extensive walking trails connect the ruins to viewpoints overlooking Lake Tsukui. It serves as a designated prefectural park managed by the Kanagawa Prefectural Park Association. The elevation provides natural vantage points used historically for surveillance. The park's layout preserves the topographical challenges of the original castle site.
The observation area near the peak of the ruins, offering a panoramic view of Lake Tsukui and the surrounding mountains.
Wear sturdy hiking footwear, as the trails involve steep inclines and uneven, unpaved surfaces.
Bring insect repellent during the warmer summer months as the park is heavily forested.
Carry water and snacks, as there are no food vendors within the park boundaries.
Do not attempt the trails in light footwear like sandals, as the incline and natural surface pose a slipping hazard.
Stay on marked trails to protect the ruins and local vegetation; carry all trash out of the park.
