Rosera is an assembly constituency in Samastipur district in the Indian state of Bihar. The seat is reserved for scheduled castes.OverviewAs per Delimitation of Parliamentary and Assembly constituencies Order, 2008, No. 139 Rosera (Vidhan Sabha constituency) is composed of the following: Rosera community development block; Phulhara, Lilhaul, Singhia-I, Singhia-II, Singhia-III, Mahen, Wari, Nirpur Bhaririya, Bangarahta, Hardiya, Mahra and Keothar of gram panchayats of Singhia CD Block; Shankarpur, Jakhar Dharampur, Ghiwahi, Dasaut, Rahiar North, Rahiar South, Ballipur, Bandhar, Karain, Raniparti and Rajaur Rambhadrapur gram panchayats of Shivaji Nagar CD Block.Rosera (Vidhan Sabha constituency) is part of No. 23 Samastipur (Lok Sabha constituency).Election results1977-2010In the 2016 Election Mahagathbandhan in Bihar seat went to Congress. Dr ashok Ram won the Rosera seat defeating his nearest rival Manju Hajari.In the 2010 state assembly elections, Manju Hajari of BJP won the Rosera seat defeating her nearest rival Pitamber Paswan of RJD. Contests in most years were multi cornered but only winners and runners are being mentioned. Gajendra Prasad Singh of RJD defeated Ashok Kumar of JD(U) in October 2005 and February 2005. Ashok Kumar of JD(U) defeated Gajendra Prasad Singh of RJD in 2000. Gajendra Prasad Singh of Janata Dal defeated Ramashray Roy of Congress in 1995 and Rama Kant Jha of Congress in 1990. Bhola Mandar of Lok Dal defeated Satyendra Narain Choudhary of Congress in 1985. Ramashray Rai of Congress (I) defeated Ram Lakhan Singh of Janata Party (SC) in 1980. Prayag Mandal, Independent, defeated Ramashay Rai of Congress in 1977.