The longest river on the Iberian Peninsula, reaching the sea at Lisbon through a broad estuary.
Length
1,038 km
Source
Montes Universales, Spain
Mouth
Atlantic Ocean (Lisbon)
Continent
Europe
Countries
Spain & Portugal
Did you know?
The medieval city of Toledo sits in a dramatic loop of the Tagus, almost encircled by the river on a rocky hill.
Little-known fact
From the Tagus estuary at Lisbon, explorers set sail in the Age of Discovery to map the world.
Highlights
- Longest river in Iberia
- Encircles historic Toledo
- Launched Age of Discovery voyages
Life in the Tagus
The fish and animals, waterbirds and water plants — including some of the rarest — that this water supports.
Animals & fish
Atlantic salmon
The “king of fish” — it is born in a river, grows at sea, then fights its way back upstream to spawn where it hatched.
Eurasian otter
A sleek, playful hunter whose return to a river is a sign the water has run clean again.
Waterbirds
Grey heron
A patient, statue-still angler that stalks the shallows of rivers and lakes across the Old World.
Mallard
The familiar green-headed dabbling duck — ancestor of most domestic ducks — found on waters worldwide.
Interactive · 3D journey
Journey of a river · source → sea
Every river runs the same great journey — from an icy mountain spring, down through gorges and looping meanders, to a wide delta where it meets the sea. Tap a stage to follow the water downstream.
Tip: hover to tilt the valley · tap a stage to float downstream
The Source
Every river begins high up — in a mountain spring, a melting glacier or a boggy upland. The water is cold, clear and fast, tumbling down the steepest ground of its whole journey.
Landforms here