The entire area in which water drains across, under, and through, on its way to a particular body of water is called a watershed.  The watersheds in Western Shasta County all eventually empty into the Sacramento River.  In Western Shasta County we have identified 13 major watersheds, shown below.  Each one is unique due to its size, shape, ownership, and types of vegetation.

There are numerous creeks in Shasta County, but typically the watershed is named for the major creek, which usually has many tributaries draining into it before it empties into the Sacramento River.  For instance, the Cow Creek watershed has five main tributaries (Little Cow, Oak Run, Clover, Old Cow, and South Cow), as well as many other minor tributaries, all coming together before emptying into the Sacramento.  Other areas have numerous small watersheds without a single major focus, so they are lumped together as "Shasta West" and "Upper Sacramento."