The roughly watershed of the Shasta River consists of a semi-arid farming valley entirely in Siskiyou County. It is adjacent to the Scott River on the west, Butte Creek on the east, and the main Klamath River on the north. The watershed is located east of the Klamath Mountains and northwest of Mount Shasta. Some towns in the watershed include Weed, Edgewood, Gazelle, Big Springs, Grenada, Montague, and Yreka. Major bodies of water include Lake Shastina (Dwinnell Reservoir) and Trout Lake.
