Big Sage Reservoir is an artificial lake in Modoc County, California and Modoc National Forest.

Its waters are impounded by Big Sage Dam, which was completed in 1921 (104 years ago) (1921).

The lake discharges into Rattlesnake Creek,[2] a tributary of the Pit River.

Hot Springs Valley Irrigation District owns the dam.

[2] Facilities include a campground and boat ramp, both located just north of the dam.