“Mahnar Bazar” is a municipality, block and Sub-division in Vaishali district of Bihar state in India. It is also the main market to all nearby ward areas and villages. It is a Vidhansabha Constituency headed by the Mla 'Dr. Achyuatanand Singh' . It comes under Hajipur Lok Sabha Constituency. It is a nagarpalika divided into many wards. It has its own police station and land registration office . The area has well-equipped government hospital and animal hospital. The town has all the facilities like cinema halls, health facilities, market complexes, hotel and motel, petrol pumps, bus stand, government and private banks, gyms, gas agency, Central Board of Secondary Education Board affiliated schools, state government affiliated schools, colleges and other good private educational institutions and coaching institute. And it is also connected to the district headquarters by both rail and road routes through state highway . It is among the fastest-growing towns of the district. There is a railway station Mahnar Road about 5 km from the market where some super fast trains also stops. It has a well-established market area with complexes and food joints and shops of all daily needs which is also the main market for the people of the town and nearby villages. Weekly markets are also organized close to the sub-division office on the day basis called as "Pethiya" like "Sukar or Juma Pethiya" on Friday, which belongs to famous prominent Zamindar family of Babu Abdul Hafiz Khan, where the local farmers sell their crops, vegetables, oils, edible things and all the variety of spices. these haats act as an agri marketing joint for the farmers It is the common and cheap market for all nearby villages in that area. There are many religious places in the locality. An yearly fair is organized near the old and famous Ganinath temple in the Cinema Road area of Mahnar. And a yearly urs is also organized on mazar of Khaki baba in which people of all religions come and worship on that day. The famous mosque of Mahnar is Jama Masjid situated in the main market area. It is also going to be the big industrial area in future due to connectivity to the state capital patna . Investors are taking interest in the area due to its good connectivity to the capital Patna and future aspects as a new town. Some people have started water bottling plant and other type of industries in this area. But the main source for income is agricultural activities for mostly of the farmers. A jail is being proposed to be built near the pethiya and subdivision office on the way to station road as land has been acquired by the government. Mahnar is also the hometown of many prominent leaders of Bihar. Sri Ramvilas Paswan MP of hajipur & cabinet minister in government of India is also very attached to this area and Sri Raghubansh Prasad Singh (born in village Shahpur of mahnar) former cabinet minister in government of India and former MP of Vaishali constituency. Ramakishore singh alias rama singh current MP of Vaishali is the resident of mahnar.Current Mla Dr Achyutanand singh is also the resident of mahnar vidhansabha. and many former leaders and independence movement leaders. Famous localities of Mahnar are Cinema Road where Ganinath temple is situated, Madan chowk which is in the main market, Kharjamma area near Pethiya and Subdivision Office, Murauwatpur area of ‘Pathans’ and Lawapur & Hassanpur of ‘Yadavas’. Mahnar has a very rich culture and people of all religions live here peacefully. In recent development, a proposed power sub-station is to be built near the sub-division office on the station road for that land has been acquired by the government. Development and industrialisation is going on as all the area is connected with main and approach roads. and this area is also becoming a real estate business hub the connectivity to this area will be more faster and closer after becoming of proposed Six lane Ganga Expressway Project Connecting Didarganj Patna to Biddupur area of Mahnar subdivision.
As of 2001[update] India census, Mahnar Bazar had a population of 37,354. Males constitute 52% of the population and females 48%. Mahnar Bazar has an average literacy rate of 43%, lower than the national average of 59.5%: male literacy is 52%, and female literacy is 33%. In Mahnar Bazar, 20% of the population is under 6 years of age.