Изер өзені: Аты, географиясы және тарихы

Many riverside communes have incorporated the Isère's name into their own, for example, Sainte Hélène sur Isère and Romans sur Isère. The department of Isère is likewise named after the river.

The name Isère was first recorded under the form Isara, which means "the impetuous one, the swift one." Not originally a Celtic word, it was very likely assimilated by the Celts in ancient times. This word is related to the Indo European *isərós, meaning "impetuous, quick, vigorous," which is similar to the Sanskrit isiráḥ इसिरः อิสิระ with the same definition. It was probably based on the reconstructed Indo European root *eis(ə) (and not *is), which incidentally has not been found in the Celtic languages of the British Isles. and runs through a wide variety of landscapes: from its source near the Italian border in the western Alps, it crosses the Pays de Savoie and the Tarentaise Valley, cuts between the Chartreuse and Belledonne mountain ranges, follows the Vercors Massif, passes through the Dauphiné province, and finally meets with the Rhône at the foot of the Vivarais.

The upper valley of the Isère is called the Tarentaise, and its middle valley the Grésivaudan. The lower valley constitutes a section of the Plain of Valence (also called the Valentinois) and is characterized by the river's deep, winding channel. Instead of widening its banks over time, the Isère has dug deeper into its bed, forming stepped fluvial terraces. The valley has clearly defined borders and is relatively narrow, not exceeding in breadth. The repetition of alluvial deposition (during periods of Quaternary glaciation) and overdeepening (during interglacial periods), known as a fluvioglacial system, led to the formation of several stepped terraces in the lower Isère valley, like the one on which Saint Marcel lès Valence is built. This occurred through the massive accumulation of alluvium from the Isère on top of a bed of Miocene molasse. Today, these terraces still define the geography of the Plain of Valence.

The Isère initially merges with one of the Rhône's diversion canals, built for navigational purposes, at Pont de l'Isère. At the southern tip of La Roche de Glun (a commune on an island formed by the canal), the Isère Dam drains part of the water back into the Rhône and permits the Isère to continue its course alone until it passes through the Bourg lès Valence Dam and reaches its final junction with the Rhône.

The length of the Isère is , and its drainage basin covers From its sources to Sainte Foy Tarentaise (except for those sources having a slope of around 25%), the average slope of the Isère is 5.1%, in a more or less confined valley (forests, gorges, and higher up, grasslands). As far as Moûtiers, the slope measures 1.18%. Before the river's confluence with the Arly, its slope is only 0.53%. The slope decreases to 0.136% until Grenoble. Downstream from Grenoble, it measures 0.1%. The flow of the Isère was observed over a period of 58 years (between 1956 and 2015) at Beaumont Monteux in the Drôme department, situated near the river's confluence with the Rhône. The discharge of the river at Beaumont Monteux measured
The Isère's large seasonal fluctuations are typical of rivers fed in large part by snowmelt, with springtime flooding raising the average monthly discharge between and from April to July (peaking in May and June), and low water levels in autumn and winter, from August to February, with a minimum average monthly discharge of in September. can drop to during a five year dry spell, and QIX 5 are and , respectively. QIX 10 is QIX 20 reaches , while QIX 50 rises to ,). The specific discharge is 27.9 liters per second per square kilometer of drainage basin.