Colombo
| District Population | 2,310,136 |
| Population Density | 3417 Persons / Km2 |
| Land Area | 699 Km2 |
| Birth Rate | 15.7 / 1000 population |
| Death Rate | 6.7 / 1000 population |
| Source: Census of Population and Housing, 2012 (Provisional) | |
Gampaha
| District Population | 2,294,806 |
| Population Density | 1711 Persons / Km2 |
| Land Area | 1,387 Km2 |
| Birth Rate | 14.4 / 1000 population |
| Death Rate | 5.6 / 1000 population |
| Source: Census of Population and Housing, 2012 (Provisional) | |
Kalutara
| District Population | 1,217,566 |
| Population Density | 773 Persons / Km2 |
| Land Area | 1,598 Km2 |
| Birth Rate | 15.4 / 1000 population |
| Death Rate | 6.3 / 1000 population |
| Source: Census of Population and Housing, 2012 (Provisional) | |