Kerzhinski Nature Reserve, Nature reserve in Nizhny Novgorod Oblast, Russia

Kerzhinski Nature Reserve is a strict zapovednik in the middle Kerzhenets basin, Bor and Semenov districts, Nizhny Novgorod Oblast. Its 46,856 hectares are about 60% pine forest and 35% small-leaved forest, with roughly 30 peat bogs; the south and east are riverine wetlands. Dead pale trunks stand in grass before a band of living conifers and a narrow blue channel.

The reserve was established on 23 April 1993 in the middle basin of the Kerzhenets River, in the Bor and Semyonovsky districts. Its territory had been a centre for scientific study of local nature since 1933. In 2002 it became part of the UNESCO biosphere reserve "Nizhegorodskoye Zavolzhye".

The reserve's name comes from the Kerzhenets River, whose middle basin it occupies. Since 2002 it has coordinated the UNESCO biosphere reserve "Nizhny Novgorod Zavolzhye", which also takes in the Voskresenskoye Povetluzhye nature park, the Kilemarsky and Varnavinsky zakazniks and 20 natural monuments. A visitor centre has been opened, and three ecotourist routes — floodplain, swamp and forest — are arranged with the reserve's staff.

The reserve is mostly closed to the general public; visits are arranged with park management for scientists and environmental-education purposes. Three ecotourist routes exist: a floodplain tour, a swamp tour and a forest tour. A visitor center operates, and the main office is in the town of Rustai.

The reserve's reintroduction work targets the muskrat, the willow ptarmigan and the forest reindeer, species lost to the territory; a 1972 fire killed about 20% of the trees, and beaver activity is studied as the landscape recovers from logging and fire.