| Maha Oya | |
| Pushpin Map: | Sri Lanka |
| Length: | 134km (83miles) |
| Source1 Location: | Nawalapitiya, Aranayake |
| Mouth Location: | Kochchikade, Negombo |
| Mouth Elevation: | Sea level |
| Bridges: | Mawanella Bridge |
The Maha Oya (Sinhala; Sinhalese: මහ ඔය,) is a major watercourse in the Sabaragamuwa Province of Sri Lanka. It measures approximately 1340NaN0 in length.[1] It runs across four provinces and five districts. The Maha Oya has 14 water supply networks to serve the need of water and more than 1 million people live by the river.[2]
Its catchment area receives approximately 3,644 million cubic metres of rain per year, and approximately 34 percent of the water reaches the sea. It has a catchment area of 1,510 square kilometres.[3]