Koderma district is plateau territory and around 60% of the total area is covered with forests.

The first dam of the Damodar Valley Corporation, at Tilaiya, was built across the Barakar River and inaugurated in 1953.

[1][2][3] Note: The map alongside presents some of the notable locations in the district.

According to the 2011 Census of India, Jainagar had a total population of 8,389, of which 4,359 (52%) were males and 4,030 (48%) were females.

The total number of literate persons in Jainagar was 5,557 (79.69% of the population over 6 years).