Bogdan was declared a nature reserve on 29 March 1972 to protect an old-growth beech forest and recategorized as a managed reserve in 1999. It spans an area of 113 ha or 1.13 km2. Its territory is state-owned. The lowest point within its territory is 1,360 m, accounting for a denivelation of 244 m. The average altitude is 1,482 m. There are not permanent rivers within the limited territory of Bogdan but the river
Topolnitsa just southwest of the reserve and its right stem the Kriva spring in its vicinity on the northern slopes. On the southern slopes flow small streams forming one of the main stems of the river
Luda Yana, while on the northeastern slopes several small streams belong to the
Stryama basin. The soils are
Cambisols. The ecosystems of the reserve are relatively homogeneous and the predominant
biotope are the European beech (
Fagus sylvatica) forests some 140–170 years old on average. Meadows form the only other biotope, covered a limited area of 4.6 ha. == Flora ==