The Segre (Catalan pronunciation: [ˈsɛɣɾə] or [ˈseɣɾe]; French: Sègre) is a river tributary to the Ebro (Ebre in Catalan) with a basin comprising territories across three states: France, Andorra, and Spain.

[2] It follows a western direction all along the Cerdanya (Cerdagne) Valley, and crosses the town Saillagouse, the Spanish exclave Llívia, and Bourg-Madame.

It enters Spain at Puigcerdà and continues west until La Seu d'Urgell, where it meets the Valira River coming from Andorra.

From this point, it adopts a south-western course across the pre-Pyrenees (with several dams along its gorges) and the western plains of Catalonia.

The river Segre is an essential feature of the Lleida's geography, dividing the city in two.