Kalaiya Sub-Metropolitan City is one of the 16 municipalities in Bara District of Madhesh Province. As per the 2021 census, the sub-metropolitan city has a total population of 136,222, comprising 70,358 males (51.6%) and 65,864 females (48.4%), with a literacy rate of 68.1%. Spanning 108.94 square kilometers, Kalaiya Sub-Metropolitan City exhibits the population density of 1,250 people per square kilometer. Administratively, it is divided into 27 wards.
According to the latest publicly available report of the Center for Education and Human Resource Development (CEHRD), Kalaiya has 117 schools. Of these, 42 are private and 72 are public. The breakdown includes 94 pre-schools, 115 basic schools, and 33 secondary schools. Among the secondary schools, 11 offer +2 programs.
Some of the popular schools within the metropolitan area include Durga Secondary School Bara, Bal Ekta English Boarding School, Nepal Ratriya Secondary School, Kalaiya Galaxy Public School, and Nepal Rastriya Secondary School.