It is located in the west of the republic and is the only district on the right bank of the Volga River.

The area of the district is 1,730 square kilometers (670 sq mi).

[4] Within the framework of administrative divisions, Gornomariysky District is one of the fourteen in the republic.

[2] The town of Kozmodemyansk serves as its administrative center, despite being incorporated separately as a town of republic significance—an administrative unit with the status equal to that of the districts.

[5] The town of republic significance of Kozmodemyansk is incorporated separately from the district as Kozmodemyansk Urban Okrug,[5] but serves as the administrative center of the municipal district as well.