The local body was formed by merging five VDCs namely Rigaun, Gumdi, Phulkharka, Baseri and Budhathum.

The population of the rural municipality is 21,784 according to the data collected on 2017 Nepalese local elections.

At the time of the 2011 Nepal census, Gangajamuna Rural Municipality had a population of 21,784.

[3] In terms of ethnicity/caste, 30.0% were Tamang, 18.9% Chhetri, 13.7% Gurung, 11.4% Ghale, 6.7% Hill Brahmin, 4.9% Newar, 4.4% Kami, 4.3% Magar, 2.9% Sarki, 1.9% Damai/Dholi, 0.4% Gharti/Bhujel, 0.3% Rai, 0.1% Musalman and 0.1% others.

[6] As per 2017, Gangajamuna hosts a population of 21,784 across a total area of 152.72 km2 (58.97 sq mi).