Jiayuguan or Jiayu Pass is the first pass at the west end of the Great Wall of China, near the city of Jiayuguan in Gansu province. It has also been called "Jiayuguan Pass"; however, this form is redundant since "guan" means "pass" in Chinese. Along with Juyongguan and Shanhaiguan, it is one of the main passes of the Great Wall.
The pass is located at the narrowest point of the western section of the Hexi Corridor, 6 kilometers southwest of the city of Jiayuguan in Gansu. The structure lies between two hills, one of which is called Jiayuguan Hill. It was built near an oasis that was then on the extreme western edge of China.
The pass is trapezoid-shaped with a perimeter of 733 meters and an area of more than 33,500 square meters. The total length of the city wall is 733 meters and the height is 11 meters.
There are two gates: one on the east side of the pass, and the other on the west side. On each gate there is a building. An inscription of "Jiayuguan" in Chinese is written on a tablet at the building at the west gate. The south and north sides of the pass are connected to the Great Wall. There is a turret on each corner of the pass. On the north side, inside the two gates, there are wide roads leading to the top of the pass.
Jiayuguan consists of three defense lines: an inner city, an outer city and a moat.
Information based on http://en.wikipedia.org/wiki/Jiayuguan_%28pass%29