Bihar state has most of the longest road and rail bridges in the country and 11 new road bridges in the state of Bihar are under construction in various districts such as Gandak Bridge at Sonepur,Kachchi Dargah Bidupur Bridge,Bakhtiyarpur Tajpur Bridge and Arrah Chhapra Ganga Bridge.
Kacchi Dargah Bidupur Bridge is under construction 6 lanes roadway bridge,connecting Kacchi Dargah and Bidupur. On completion in 2020, The 9.76 km long road bridge over river Ganges will be the longest bridge of India on river.
The 5.6 Kilometers long Mahatma Gandhi Setu, connecting Patna in the south to Hajipur is the longest river bridge in India. Mahatma Gandhi Setu over the river Ganges is also longest cantilever bridge of Asia.
Bakhtiyarpur Tajpur Bridge is one of the under construction bridge across the river Ganges,connecting Bakhtiyarpur in Patna and Tajpur in Samastipur. The project has four-lane approach road and the total length of bridge is 5.55 km over Bakhtiyarpur bypass of NH-31 near Karjan village.
Vikramshila Setu is the third longest bridge in India, across the Ganges river near Bhagalpur. The 4.7 km long two lane bridge connects Bhagalpur to Purnia and Kathiar.
Ganga Rail Road Bridge across the river Ganges is 4.5 km long roadway and railway link bridge, connecting Digha Ghat and Pahleja Ghat. Digha Sonepur Rail Road Bridge is second railway bridge across the Ganges in Bihar.
Ara-Chhapra road bridge is high level bridge across river Ganga, between Ara and Chhapra. The 4.35 km long four Lane bridge would provide a link between northern and southern part of Bihar.
Munger Ganga Bridge is one of the rail-cum-road bridge in Bihar, under construction across the Ganges river. The 3.692 km long bridge connects Jamalpur Junction on the Sahibganj Loop line.
Nehru Setu also known as Upper Son Bridge is is the second longest railway bridge in India built across the Son River. The 3,064 metres long is the fifth largest bridge in India.
Jawahar Setu is built between Dehri-on-Son and Son Nagar across the Son River. The 3,061 metres long road bridge is part of the NH 2 also known as the Grand Trunk Road.
Rajendra Setu across the Ganges was the first bridge to link North and South Bihar. This road-cum-rail bridge was inaugurated by President of India and carries a two lane road and a single line railway track.
Dhanaha Ratwal bridge in Bagaha is known as Gautam Buddha bridge, The 1.8km long bridge will provide connectivity to blocks of Sakara, Bhitaha, Madhubani and Piprasi.
Koilwar Bridge is a steel lattice girder bridge, situated on the river Son. The bridge is 1,440 meter long and used to be the longest bridge in the Indian subcontinent till 1900.