Located at the foot of Mianshan Mountain in the northeast of Pingding county, Niangzi Pass was built in the Ming Dynasty and it is the ninth pass on the Great Wall of China. Niangzi Pass was originally known as Weize Pass and was said to be built when Princess Pingyang of Tang Dynasty was stationed there. As Princess Pingyang's troops were called women (Niangzi) soldiers, the pass is also called Niangzi Pass. Situated beside mountains and waters, the ancient castle has two gates. The east gate is a common brick gate carved with Niangzi Pass of Zhili. Above the gate, there is a castle for inspecting soldiers and observing enemies.
Niangzi Pass has many waterfalls, among which the most famous is the Hanging Waterfall on the northwest side, also known as Niangzi Pass Waterfall and Water Curtain Cave Waterfall. The waterfall, with a width of 6.5 meters and a fall of 40 meters, was praised by ancient and contemporary scholars such as Wang Shizhen of the Ming Dynasty and contemporary scholar Guo Moruo. Before and after Niangzi Pass, there are many historical relics related to Princess Pingyang, such as the Princess's Washbasin, General Appointment Platform and Summer Shelter Pavilion on the top of Mianshan Mountain.