The district is elongated from west to east.
A major part of the district belongs to the basins of the Mezen River (with the main tributaries the Pyoza and the Kimzha) and the Kuloy River (with the Nemnyuga and the Soyana), which both end up in the Mezen Bay of the White Sea.
Areas on the White Sea coast drain directly into the sea, and some areas in the northeast of the district drain into the Pyosha River and other rivers of the Barents Sea basin.

Almost the whole of the district is covered by coniferous forests (taiga).
The northern part of the district is transitional area between taiga and tundra (lesotundra).
There are many glacial lakes across the district.
The biggest lakes are east of the Mezen, Lake Varsh (shared with Nenets Autonomous Okrug), Lake Pocha, and Lake Vyzhletskoye.

The district also includes Morzhovets Island which separates the Mezen Bay from the entrance of the White Sea.
The island is the only part of the district which lies above the Arctic Circle.

The part of the district located east of the Mezen is essentially unpopulated, with the exceptions of the right bank of the river and of several villages in the valley of the Pyoza.
The district is elongated from west to east. A major part of the district belongs to the basins of the Mezen River (with the main tributaries the Pyoza and the Kimzha) and the Kuloy River (with the Nemnyuga and the Soyana), which both end up in the Mezen Bay of the White Sea. Areas on the White Sea coast drain directly into the sea, and some areas in the northeast of the district drain into the Pyosha River and other rivers of the Barents Sea basin.
Almost the whole of the district is covered by coniferous forests (taiga). The northern part of the district is transitional area between taiga and tundra (lesotundra). There are many glacial lakes across the district. The biggest lakes are east of the Mezen, Lake Varsh (shared with Nenets Autonomous Okrug), Lake Pocha, and Lake Vyzhletskoye.
The district also includes Morzhovets Island which separates the Mezen Bay from the entrance of the White Sea. The island is the only part of the district which lies above the Arctic Circle.
The part of the district located east of the Mezen is essentially unpopulated, with the exceptions of the right bank of the river and of several villages in the valley of the Pyoza.
Mezensky District