The Mahatma Gandhi Setu bridge , over the river Ganga in Patna is India's longest river bridge . The bridge spans over 5.575 km from Hajipur at the north end , to Patna at the south end . Be4 the bridge was constructed , people who wanted to go to the north of the Bihar , had to cross the river using boats or small ships , steamers or take a longer rail route . The bridge was Inaugurated in may 1982 by then PM , Mrs. Indira Gandhi .
