Colombo derived its name from a classical origin" kolon thota" which means port on the river kelani. However many is of the opinion that a Sinhalese origin is also behind the framing of the name Colombo. The Sinhalese name "Kola Amba Thota" meaning 'harbor with leafy mango trees' also goes in giving the capital city its present name.  Colombo became the capital city of Sri Lanka only in the year 1815, when it gave itself up to the authority of the British Empire. However, the position of acting as the capital was retained after Sri Lanka gained independence in 1948. Colombo came to be regarded as the country's commercial hub in 1978 when the administrative office was shifted to Sri Jayewardenepura Kotte. Colombo has been well known by traders from almost 2000 years ago. The Romans, Chinese, Arab traders preferred this port city as it enhanced their trade to a great extent. Portuguese set their feet on the soil of Sri Lanka in 1505 and chose this country mainly for the benefit of their spice trade. During the period of the Dutch rule, Colombo served as the capital of the Maritime Provinces put under the strict control of the Dutch East India Company. The British were the last to invade the port city in 1796. However, the port city gained the status of being the capital only in 1815. Until and unless the Municipal council was established in January 1866, the city was governed by the Government Agent of the Western Province. In historical terms, Colombo refers to the area around the Fort and the Pettah Market. In recent times Colombo is identified with the city limits of the Municipal Council of Colombo.

Before 1999, Colombo Municipal Council area was regarded as only one Divisional Secretariat Division. Later, this office was divided in to two; namely, Colombo and Thimbirigasyaya. There are 47 urban divisions in Colombo Municipal Council. Though the Grama Niladhari divisions were established according to those urban divisions, another 8 Grama Niladhari divisions were established considering the population density. Accordingly the total no. of Grama Niladhari divisions is 55. Out of those 55, 30 belong to Colombo Divisional Secretariat. According to the 2001 census, Colombo Divisional Secretariat Division had the highest population density which was 377,396. It was estimated to be 425,000 by the year 2005. Since then, this office has faced so many difficulties and developed a mechanism to serve the public more effectively efficiently.