Mt. Lidong, with an altitude of approximately 1914 meters, features a rare first-class triangulation point and a supplementary point marked by the provincial government. Due to its strategic geographical location, during the Qing dynasty, it was used as a military encampment site, hence its name. In the Japanese colonial era, as the Japanese army frequently faced attacks from the Tayal people in the upper reaches of the Dahan River, they built a fortress on the mountain peak and deployed cannons to control nearby coastal villages. Although Mt. Lidong no longer holds strategic advantages today, the remaining traces of the ancient fortress serve as a testament to its glorious military history. The summit offers a panoramic view, allowing one to gaze at the majestic landscapes of Mt. Xue, Daba Jianshan, and Nanhu Dasha. Located on the ridge that marks the boundary between Jinshe Township, Hsinchu County, and Fuxing Township, Taoyuan County, one can access Mt. Lidong via the trailhead at Zhudong, then pass through Jinshe to the trailhead at the Yu Lao Police Station. Take the left path and continue on the farm road to Lidong Mountain Villa. The mountain trail behind the villa, a leisurely two-and-a-half-hour hike, leads to the ancient fortress on the summit. The air is refreshing, with fragrant flowers and lush green grass; however, only the fortress gate and surrounding walls remain.