The reserve protects a wide variety high-altitude, continental climate flora and fauna complexes: larch taiga, cedar thickets, mountain tundra, and sub-alpine meadows of the Delyun-Uran and Kodar Mountains.

The reserve is located in the southeast of the Bodaybinsky District of Irkutsk Oblast, 150 km east of the regional city of Bodaybo.

It ascends from Lake Oron in the west to the top of the Kodar Mountain ridge in the south and east of the reserve.

The dominant vegetation is light coniferous taiga with Larix gmelinii forming the canopy in areas with low snow cover.

[5][6] Because reserve is in a temperate zone far from the oceans and with mountain terrain, it experiences sharply continental climate.

From the river valley floors to about 1,200 metres (3,900 ft) is a forest zone of primarily larch trees (Larix gmelinii) and some Scots pine on sandy soils.

Above 2,700 metres (8,900 ft) is a bald mountain zone above which the only plant life is a few types of lichen.