Mari Depression

The Mari Depression () is a depression in Gornomariysky District, Mari El, Russian Federation.
Geography.
The depression is located on the left side of the Volga, from the western borders of the Mari El to the Bolshaya Kokshaga River. The average height of the depression is between and and there are many small lakes and swamps. The area is now partly flooded by the Cheboksary Reservoir. 
Dunes.
There are ancient dunes covered with forests located between the rivers.