Maharajganj is located at . It has an average elevation of 66 metres (216 feet).
India census, Maharajganj had a population of 20,878. Males constitute 50% of the population and females 50%. Maharajganj has an average literacy rate of 50%, lower than the national average of 59.5%: male literacy is 61%, and female literacy is 40%. In Maharajganj, 19% of the population is under 6 years of age.