Sundar Haraicha (Nepali: सुन्दर हरैचा) is a municipality in Morang District of Koshi Province in Nepal.

[1] It consists of the town centres of Biratchowk and Gothgaun which are parts of the Greater Birat Development Area which incorporates the cities of Biratnagar-Itahari-Gothgau-Biratchowk-Dharan[2] primarily located on the Koshi Highway in Eastern Nepal, with an estimated total urban agglomerated population of 804,300 people living in 159,332 households.

[4][5][6] At the time of the 2011 Nepal census, the localities formed had a joint population of 80,518 people living in 18,610 individual households.

[8] The total population of all the predecessor villages of this municipality stands at 80,518 people living in 18,610 individual households in 2011 Nepal census.

Earlier, the municipality was formed merging the three existing villages, Haraicha, Mrigaulia, and Indrapur, in May 2014.