Kamalpur, Sultanganj

As of 2011, Kamalpur had a population of 525, in 83 households.^[1]: 160 This population was 53.5% male (281) and 46.5% female (244). The 0-6 age group numbered 56 (36 male and 20 female), or 10.7% of the total population. 94 residents were members of Scheduled Castes, or 17.9% of the total.^{[2]: 124–5}

The 1981 census recorded Kamalpur as having a population of 495 people, in 94 households.^{[3]: 166–7}

The 1961 census recorded Kamalpur as comprising 1 hamlet, with a total population of 357 people (192 male and 165 female), in 69 households and 41 physical houses. The area of the village was given as 279 acres.^[4]: xciv

As of 2011, Kamalpur had 1 primary school; it did not have any healthcare facilities. Drinking water was provided by hand pump, and tube well/borehole; there were no public toilets. The village had a post office but no public library; there was at least some access to electricity for all purposes. Streets were made of kachcha materials.^{[1]: 160–5}