Deadwood Dam is located in west-central Idaho on the Deadwood River about 25 miles above its confluence with the South Fork of the Payette River and about 90 miles above Black Canyon Diversion Dam. The damsite is located in a narrow canyon where the Deadwood River has cut into granite bedrock, approximately 53 miles northeast of Boise, Idaho. The dam lies on the western slope of the Sawtooth Mountains with elevations in the basin varying from 5311 feet by the dam to about 8,696 feet at Price Peak. Deadwood Reservoir is three and one half miles long and covers 3,180 acres. Deadwood Dam is a concrete-arch structure with a structural height of 165 feet and a total capacity of 154,000 acre-feet, providing a regulated flow for the powerplant at Black Canyon Diversion Dam and for irrigation in the Payette Division and Emmett Irrigation District.
Foundation: Hard, sound granite, massive at left abutment and fissured with sheet and block joints at right abutment. Two tightly filled fault-zone seams cross foundation on right side.