Explore Sri Lanka’s rivers

How to read the river map

Start with a name you know, such as Mahaweli, Kelani or Kalu Ganga. Search in English or with an available Sinhala or Tamil name. Selecting a river brings its mapped sections into view. Choose Whole island whenever you want to see its position on the island again.

• Follow the highlighted line. It shows the mapped sections of your chosen river. The line becomes easier to inspect as you zoom in.
• Notice gaps and dashed sections. A gap means a connecting course has not been verified. Attanagalu Oya has one dashed, estimated join; its profile explains it.
• Use places for reference. Open Map layers at the top right and switch on Major cities. City dots, water bodies and extra river sections are optional and start switched off.
• Check the profile. It shows river names, available learning notes and links to the map's sources. A missing name is shown as awaiting a source.

Moving around

Drag the map to move it. Use the + and - buttons, or pinch your trackpad to zoom. In the full-screen playground you can also scroll to zoom. On this guide, click the map before scrolling to zoom; otherwise scrolling continues down the page. Zoom follows the pointer, so aim at the part you want to inspect.

Prefer a keyboard? Tab to the map or a river, use + and - to zoom and the arrow keys to move. Home returns to the whole island. Search and the river list offer another way to select a river.

What can a river map help you notice?

Compare the shapes and positions of rivers, look for places where mapped lines meet and practise describing locations. Rivers can receive water from smaller streams, and water can collect in a reservoir behind a dam. For an introduction to these ideas, see the USGS Water Science School's guide to rivers, streams and creeks.

This map shows approximate sections rather than every river's complete journey. A line's drawing order does not tell you which way water flows. Use the activities above to practise asking what a map shows and what still needs another source.

Names and map notes

All 45 river records include approximate source-mapped geometry. Sinhala labels are available for all 45 rivers; Tamil labels appear where a source is available. Kukul Oya's Sinhala label is provisional, based on a bilingual local place name while a direct Sinhala river-name source is still needed.

Expand Browse all 45 rivers below to load the names and references. You can also open the full river list and sources, which works without JavaScript. Each river has expandable citations and coverage notes, followed by the full publication details and reuse terms.

About the map data

River sections come from an OpenStreetMap snapshot dated 9 October 2026: © OpenStreetMap contributors, via Geofabrik, under ODbL 1.0. The country outline comes from geoBoundaries. City reference points come from Natural Earth, version 5.1.2, under its public-domain terms.

Optional water and river backgrounds come from an older export with an unknown snapshot date. They provide context and do not fill gaps in a selected river. Use the explorer for learning and discussion; it does not establish river lengths, exact starting points or travel routes.