Oleninsky District (Russian: Оле́нинский райо́н) is an administrative and municipal district (raion), one of the thirty-six in Tver Oblast, Russia. It is located in the southwest of the oblast and borders with Selizharovsky District in the north, Rzhevsky District in the east, Sychyovsky District of Smolensk Oblast in the southeast, Belsky District in the south, and with Nelidovsky District in the west. The area of the district is 2,675 square kilometers (1,033 sq mi). Its administrative center is the urban locality (an urban-type settlement) of Olenino. Population: 12,675 (2010 Census); 14,817 (2002 Census); 18,892 (1989 Census). The population of Olenino accounts for 38.8% of the district's total population.