Black Mountain, also called Mount Day, is a prominent peak in the Diablo Range of eastern Santa Clara County, about 10 miles from Milpitas. Rising east of Poverty Ridge and Arroyo Hondo, it is considered one of the higher mountains in its immediate area. The mountain is especially recognizable for its divided landscape, with oak woodland covering its northern half and a mostly barren southern half. Its elevated position above the Santa Clara Valley makes it visible from many valley communities, including Sunnyvale, Cupertino, Mountain View, and San Jose, as well as from Mount Hamilton and Monument Peak.