Colombo District is one of the 25 districts of Sri Lanka, the second level administrative division of the country. The district is administered by …Colombo District is one of the 25 districts of Sri Lanka, the second level administrative division of the country. The district is administered by a District Secretariat headed by a District Secretary appointed by the central government of Sri Lanka. The capital of the district is the city of Colombo. The district of Colombo was officially recorded in 2016 as having the highest income on average, per household.