Kolasib district is a district of Mizoram state with its administrative headquarters located at Kolasib town. At a very begining, Kolasib was formed as the centre of Tribal Development Block. After sometime it was promoted to a position to be administered by the Area Administrative Officer. The time when Mizoram was upgraded to a Union Territory in the year 1972, automatically on 5th May, 1975 Kolasib became the headquarters of Sub-Division which administered by Sub-Divisional Officer (Civil). Kolasib remained as a seat of administration for more than three long decades. Then finally, after the trifurcation of Aizawl district the state government of Mizoram declared the place of Kolasib, an independent administrative district in the year 1999.

Geographically, the district lies at 24°23' N latitude and 92°68' E longitude. The altitude in the district is 646 m. In the year 2021, there was a total 83.31% forest area of total geographical area. The district encompasses a geographical area of 1,382 sq km. and it is bounded by Hailakandi district on the North and North West, Cachar district on the North East, Aizawl district on the South and East and Mamit district on the West. The principal river in the district is Tlawng River. The climate of the district remains mild throughout the year. Most of its rainfall occurs in the monsoon season. The actual rainfall in the district was 2234.6 mm in the year of 2021-22.

Administration wise, the district is divided into two regional development blocks namely Bilkhawthlir and Thingdawl. Moreover, it comprises 4 towns and 49 villages. The administrative language in the district is Mizo.

According to 2011 census the district has a population of 83,955 including 42,918 are males and 41,037 are females. The district has a sex ratio of 956 (females for every 1000 males). During the year 2001-2011 the population growth rate in the district was 27.28% out of which 24.18% were males and 30.7% were females. As per 2011 census the major religion in the district is Christian with 89.58% of the total population. The population density in the district is 61 (persons per sq. km.). As per 2011 census the principal languages in the district are Lushai/Mizo with 75.93%. In the year 2020 the number of live births in the district was 1,584 out of which 783 were males and 801 were females. In the same year the number of deaths in the district was 457 out of which 304 were males and 153 were females.

The district has an agriculture-dominated economy with some government jobs. More than half of its population are engaged in agricultural activities in order to earn their livelihood. The chief agricultural products in the district are pulses, fruits, vegetables, areca nut, etc. Every year a huge chunk of revenue comes from the agricultural products in the district helps in its economy to a great extent. The district is scantily industrialised but it has some scale industries of dyes, medicine, fibres, shawls, toys, handicrafts, etc. In the year 2005-06 the gross domestic product in the district was Rs. 18,063 lakhs at current price and Rs. 13,819 lakhs at constant prices in the year 1999-2000. The net domestic product in the district during the period 2005-06 was Rs. 15,954 lakh at current price and Rs. 12,201 lakh at constant prices in the year 1999-2000. The Per Capita Income or NDDP, At Factor Cost during the period 2005-06 was Rs. 21,047 at current price and Rs. 758 at constant prices in the year 1999-2000.

The district is well known as an abode of several reputed educational institutions. It provides a platform for higher education. The Government Kolasib College under Mizoram University is one of the most recognised colleges of the district. Some other renowned Higher Secondary Schools in Kolasib are St. John's Higher Secondary School, C. Zakhuma Higher Secondary School (CZS), Madonna Open School, etc. As per 2011 census the literacy rate in the district is 93.5% including 94.57% are males and 92.38% are females. The literate population in the district is 65,895 including 34,147 are males and 31,748 are females. The illiterate population in the district is 18,060 out of which 8,771 are males and 9,289 are females.

The district has several centres of attraction which allures many travellers from different parts of the country as well as world. Tlawng River, originated from Kolasib is popular for fishing activities. The interesting locations in and around this river are the Bairabi Hydel Project, Regional Research Station of the Rubber Institute of India and an Industrial Estate. Vairengte, a beautiful place with plush green forests and some mesmerising sceneries is located at a distance of 130 kms from Aizawl. The environment of the place is very calm and peaceful. It is a perfect destination for mental relaxation. The Blue Mountain, one of the marvellous tourist spots of the district is commonly known as Phawngpui. It is an awesome place especially for lover of adventurous sports. This is also the most altitudinous peak of Mizoram. Dampa Sanctuary, located in the north western part of the hills of Mizoram is rich in various kinds of animals such as swamp deer, tigers, leopards, elephants and other unusual species. Some other notable places of interest in the district are Tamdil Lake and many more.