The Glogn (Romansh, German: Glenner) is a whitewater river in Graubünden.

The river rises near the border with Ticino and is surrounded by up to 3100m high mountains.

In the upper reaches of the river has cut a deep gorge, which has uncovered black shale in a few places.

During the snow melt and after rains the river water is usually dark gray.

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