The Gran Valira (, ) is the biggest river in Andorra. It flows through the capital, Andorra la Vella, and exits the country in the south near the Spain-Andorra road border crossing.
The Valira is a tributary to the Segre, which in turn is a tributary to the Ebro. It flows into the Segre in La Seu d'Urgell. Its main tributaries are the Valira d'Orient, the Valira del Nord and the Madriu. The Valira river system is 35 km long.