Demyansky District in the context of Firovsky District

Seliger (Russian: Селиге́р, IPA: [sʲɪlʲɪˈgʲer]) is a lake in Ostashkovsky District of Tver Oblast and (in the extreme northern part) in Demyansky District of Novgorod Oblast of Russia, in the northwest of the Valdai Hills, a part of the Volga basin. It has an absolute height of 205 metres (673 ft), an area of 212 square kilometres (82 sq mi), and an average depth of 5.8 metres (19 ft).

Lake Seliger is a large system of bodies of water linked by channels, has many small islands, and is surrounded by forests - including pine woods with many berries and mushrooms. It is one of the biggest natural lakes of Central Russia. The only outflow of the lake, the Selizharovka River, flows from the southern end of the lake and drains into the Volga after 36 kilometres (22 mi). The drainage basin of the lake includes the major part of Ostashkovsky District, the south of Demyansky District, as well as minor areas in the Firovsky District of Tver Oblast.

Ostashkovsky District (Russian: Оста́шковский райо́н) is an administrative and municipal district (raion), one of the thirty-six in Tver Oblast, Russia. It is located in the northwest of the oblast and borders with Demyansky District of Novgorod Oblast in the north, Firovsky District in the northwest, Kuvshinovsky District in the east, Selizharovsky District in the south, Penovsky District in the southwest, and with Maryovsky District of Novgorod Oblast in the west. The area of the district is 3,200 square kilometers (1,200 sq mi). Its administrative center is the town of Ostashkov. Population: 23,761 (2010 Census); 7,357 (2002 census); 8,921 (1989 Soviet census). The population of Ostashkov accounts for 76.1% of the district's total population.

Valdaysky District (Russian: Валда́йский райо́н) is an administrative and municipal district (raion), one of the twenty-one in Novgorod Oblast, Russia. It is located in the southeast of the oblast and borders with Okulovsky District in the north, Bologovsky District of Tver Oblast in the east, the territory of the closed administrative-territorial formation of Ozyorny of Tver Oblast in the southeast, Firovsky District of Tver Oblast in the south, Demyansky District in the southwest, and with Krestetsky District in the northwest. The area of the district is 2,701.63 square kilometers (1,043.11 sq mi). Its administrative center is the town of Valday. Population: 26,476 (2010 census); 29,943 (2002 Census); 32,373 (1989 Soviet census). The population of Valday accounts for 60.8% of the district's total population.

Starorussky District (Russian: Старору́сский райо́н) is an administrative and municipal district (raion), one of the twenty-one in Novgorod Oblast, Russia. It is located in the southwest of the oblast and borders with Parfinsky District in the east, Demyansky and Maryovsky Districts in the southeast, Poddorsky District in the southwest, Volotovsky District in the west, and with Shimsky District in the northwest. From the north, the district is limited by Lake Ilmen. The area of the district is 3,111 square kilometers (1,201 sq mi). Its administrative center is the town of Staraya Russa (which is not administratively a part of the district). Population: 15,063 (2010 census); 16,214 (2002 Census); 18,505 (1989 Soviet census).

Parfinsky District (Russian: Парфинский район) is an administrative and municipal district (raion), one of the twenty-one in Novgorod Oblast, Russia. It is located in the center of the oblast and borders with Krestetsky District in the north, Demyansky District in the southeast, and with Starorussky District in the southwest. The area of the district is 1,591 square kilometers (614 sq mi). Its administrative center is the urban locality (a work settlement) of Parfino. Population: 14,395 (2010 census); 16,485 (2002 Census); 17,650 (1989 Soviet census). The population of Parfino accounts for 52.0% of the total district's population.

The Pola (Russian: Пола́) is a river in Andreapolsky and Penovsky Districts of Tver Oblast and Maryovsky, Demyansky, and Parfinsky Districts of Novgorod Oblast in Russia. It is a tributary of Lake Ilmen. It is 267 kilometres (166 mi) long, and the area of its basin 74,200 square kilometres (28,600 sq mi). The principal tributaries of the Pola are the Maryovka, Kamenka, Yavon, and Polomet rivers, all from the right.

The source of the Pola is located in the Valdai Hills, at the border between Andreapolsky and Penovsky Districts of Tver Oblast, southwest of the village of Pyatygino. It flows north, making the border between these districts, and enters Novgorod Oblast. The Pola accepts the Maryovka River from the right and turns east, then it accepts the Kamenka River from the right and turns north. In the village of Veliky Zavod the river makes a loop, and at the tip of the loop, in the village of Novoye Sokhnovo, it accepts the Yavon River from the right. In Novoye Sokhnovo the Pola turns west and in the village of Kostkovo it accepts the Polomet River, also from the right. Downstream from the mouth of the Polomet, the Pola turns northwest. Close to Lake Ilmen, the Pola shares a river delta with the Lovat and the Polist.