Niaku Pol-e Kheshti is placed along one of the side routes of the old road of Lahijan to Niaku, Jisdan and Astaneh Ashrafieh which is ended in Rasht. The bridge has been erected over a branch of Shamrud and it is placed within the area of Niaku to Bazkiagurab and it is 50 meters long. It is made of brick and stone in combination with Sarooj mortar. Niaku includes a large mouth and three small ones around the main entrance. Three small mouths increase durability of the bridge. The total height from the river level is around 6.5 and its width is 5.8 meters. The bricks served in the building of the bridge are 20*20*5 and 17*17*4 centimeters. The bridge has been included in the list of Iran National Heritages. (No. 2.1443)