1990 Map of Triangle Flat

About this map

Triangle Flat and the high desert of Owyhee County are defined by a network of seasonal water sources and early mining traces. In the northern reaches, a Mine Shaft and Adit near Mammoth Creek mark where prospecting met the high plateau. The landscape transitions into deep drainages like Josephine Creek and Rock Creek, which flow toward the southern valleys. Settlement remains sparse, with human activity centered on ranching infrastructure such as the Spencer Reservoir and Twin Valley Reservoir. This environment required significant resource management, evidenced by the numerous named water points including Hardman Spring and Chimney Spring. In the southeast, the Triangle Airstrip and Antelope Ridge Road provide the primary links across this high-elevation terrain, connecting the open flats with the prominent Rose Ridge.