According to the locals, Parsa is named after the Parashnath temple situated in Mahuwan.

[3] At the time of the 2011 Nepal census, Parsa District had a population of 601,017.

As their first language, 78.4% spoke Bhojpuri, 6.1% Nepali, 5.1% Maithili, 3.8% Tharu, 2.2% Urdu, 1.3% Tamang, 0.8% Rajasthani, 0.7% Newari, 0.3% Uranw/Urau, 0.2% Hindi, 0.2% Rai, 0.1% Bengali, 0.1% Doteli, 0.1% Magar and 0.1% other languages.

[6] Ethnicity/caste: 14.5% were Musalman, 8.4% Kurmi, 7.6% Tharu, 6.6% Yadav, 5.8% Kanu, 4.7% Chamar/Harijan/Ram, 4.2% Teli, 3.2% Koiri/Kushwaha, 2.8% Chhetri, 2.7% Dusadh/Paswan/Pasi, 2.6% Hill Brahmin, 2.6% Mallaha, 2.0% Baraee, 1.9% Kalwar, 1.8% Dhanuk, 1.7% Nuniya, 1.7% Tamang, 1.6% Musahar, 1.6% Newar, 1.6% Sonar, 1.5% Bin, 1.4% Dhobi, 1.4% Hajam/Thakur, 1.4% Kathabaniyan, 1.3% Lohar, 1.3% Tatma/Tatwa, 1.2% other Terai, 1.0% Terai Brahmin, 1.0% Kayastha, 0.9% Marwadi, 0.8% Sanyasi/Dasnami, 0.7% Rajput, 0.6% Kewat, 0.6% Kumal, 0.6% Kumhar, 0.6% Magar, 0.4% Yakkha, 0.3% Dhunia, 0.3% Jhangad/Dhagar, 0.3% Kami, 0.2% Bengali, 0.2% Damai/Dholi, 0.2% Dom, 0.2% Halkhor, 0.2% Kahar, 0.2% Mali, 0.2% Rai, 0.1% Badhaee, 0.1% Gaderi/Bhedihar, 0.1% Gurung, 0.1% Halwai, 0.1% Majhi, 0.1% Natuwa, 0.1% Rajbhar, 0.1% Sarki, 0.1% Thakuri and 0.1% others.

[7] Religion: 83.1% were Hindu, 14.5% Muslim, 1.7% Buddhist, 0.4% Kirati, 0.1% Christian and 0.1% others.