The historical bridge of Mir Bahauddin is entirely brick, and the date of its construction is engraved in a very beautiful script on the inside of its largest arch, along with the holy zikr or Ali.

The openings of the arches of the bridge are wide, and are applied in a very beautiful and graceful style. Also, in order to control the extra load of the arches, four springs of the arch have been built in the form of two arches with transept and crescent arches, parallel to each other and around the largest arch.
The historical bridge of Mir Bahauddin should be considered the oldest and the largest remaining bridge on Zanjan Road, which is more than a hundred years old and is registered in the list of national monuments under number 1448. The length of the bridge is about 100 meters and its width, including the parapets, reaches 6.70 meters. The height of the bridge at its highest point above the river level is about 11 meters. The bridge has three spans with gabled arches. The middle opening is bigger than the other two openings. This bridge is built perpendicular to the river and to be in line with the road, they have given a curve to its two ends.

The abutments of the bridge are located on the paved surface and are made of pieces of cut stone and lime mortar and rise to a height of 1.40 meters above the water level. At this height, the pakar of the arch and the main body of the bridge starts with bricks of dimensions 24x5x24 cm. The width of the bases in the lowest part is about 6.80 meters. On each of the bases, two pavilions are built on top of each other.

The lower pavilion, which is shorter and has a cradle arch, is 4 meters wide and 2.3 meters high. The upper pavilion is 4.60 meters high and 4 meters wide with five and seven gable arches. These pavilions, which are repeated on other foundations, in addition to passing flood waters, also reduce the weight and pressure on the foundations. In addition to this arrangement, in order to reduce the weight of the bridge, the side spaces of the three large openings of the bridge have been hollowed out so that the arches have more power to bear the pressure.

The southern pavilions are connected by a spiral staircase. In the upstream and downstream of the bridge foundations, stone drains have been created to facilitate the flow of water. The aqueducts above the bridge are polygonal and the aqueducts below are semicircular.
The middle and larger opening of the bridge is 14 meters wide and 8.5 meters high - from the tip of the arch to the water level. The side openings are also 12.15 meters wide and about 7 meters high and are no longer used today with the construction of a new bridge.
 This bridge has been repaired in the recent period by the efforts of the General Directorate of Cultural Heritage and it has been registered in the historical register number 1484.