Spanning a territory of 12417 ha or 124.17 km2, it is the largest nature reserve in the nation and the Balkan Peninsula.

It is a strict nature reserve (1st category protected territory according to Bulgarian legislation and IUCN classification).

[1] The reserve is situated in central part of Rila in the upper valleys of two of the largest rivers of Bulgaria, the Maritsa and the Iskar.

There are a number of rare and endemic plant species under protection, such as Anthemis orbelica, Campanula transsilvanica, Draba siliquosa, Gentiana lutea, Gentiana puntata, Geum bulgaricum, Primula deorum, Soldanella pusilla, Rhodiola rosea, Valeriana montana, Nardus stricta, Juniperus communis, Vaccinium vitis-idaea, etc.

[3][5] The fauna of the Central Rila Reserve is diverse, with a number of rare species of conservational importance, including brown bear, gray wolf, European pine marten, chamois, roe deer, wild boar, black woodpecker, western capercaillie, hazel grouse, common European viper, European green lizard, viviparous lizard, river trout, etc.