The survey results of the spider fauna of Black Rock Forest (BRF), Orange County, New York for 12 years are presented. The BRF spider fauna includes 27 families, 121 genera, and 279 species. Most numerous are the Linyphiidae, which make up 26.9% of all spider fauna. Pityohyphantes subarcticus Chamberlin et Ivie, 1943, Tenuiphantes tenuis (Blackwall, 1852), and Erigone dentosa O.Pickard-Cambridge, 1894 were found for first time in the New York State region. The most diverse community was that of the deciduous forest, where 201 species were found. We also found 83 species in swamp areas; 111 species in the coniferous forest; 141 meadow species and 95 species near rivers and ponds. The most unique spider fauna were in the deciduous forest, whereas it had been previously thought the most unique fauna occurred in meadows. The richness and uniqueness of spider faunas in natural ecosystems strongly depend on the type and state of wild vegetation, which may be used for monitoring the health of the landscape.