The Sac River flows through southwestern Missouri, originating near Springfield and traveling northward until it joins the Osage River at Truman Reservoir. This sixth-order stream flows through a diverse landscape spanning 10 counties including Barton, Cedar, Christian, Dade, Greene, Hickory, Lawrence, Polk, St. Clair, and Vernon. The watershed encompasses 1,981 square miles and includes major tributaries such as Little Sac River, Turnback Creek, Sons Creek, Horse Creek, Cedar Creek, Coon Creek, Turkey Creek, Brush Creek, and Bear Creek. The river's character changes throughout its course, with clear water and gravel/cobble streambeds in southern reaches, becoming more turbid with sand and silt substrates in northern sections. Stockton Lake divides the river, creating distinct upper and lower sections with different characteristics and fishing opportunities.