The Sprague River is a tributary of the Williamson River, approximately 75 mi (121 km) long, in southwestern Oregon in the United States. It drains an arid volcanic plateau region east of the Cascade Range in the watershed of the Klamath River.
It is formed by the confluence of its North and South forks in eastern Klamath County, approximately 35 mi (56 km) ENE of Klamath Falls. The North Fork (30 mi/48 km) rises in southwestern Lake County in the Fremont National Forest near Gearhart Mountain and flows southwest. The South Fork (30 mi/48 km) rises northeast of Quartz Mountain Pass and flows WNW. The combined stream flows west through the broad Sprague Valley, past the small communities of Bly, Beatty and Sprague River . It joins the Williamson from the east at Chiloquin, approximately 10 mi north of the mouth of the Williamson on Upper Klamath Lake.
It receives the Sycan River from the north at Beatty.
