The “Pec,” as it’s called sometimes by the locals, began forming several million years ago when the glaciers inched their way across southwest Wisconsin and northern Illinois, leaving their meltwaters to begin carving a region of broad, open ridgetops, deep valleys, and steep, wooded slopes. Another batch of glaciers travelled across the Pecatonica River’s watershed some 200,000 years ago, smoothing over northern Illinois into a region of rolling hills once covered by prairies

Bending here, winding there, the “Crooked River” sometimes almost doubles back on itself, stretching 194 miles across five counties in two states. The river’s headwaters are nestled in the hills of Iowa County in the Southwest Savanna region of Wisconsin. The two branches flow south, meeting just north of the state line before continuing south to Freeport, Illinois. Here, the river cuts east and wanders through the Rock River Hill Country of northern Illinois. The Pecatonica receives the waters of the Sugar River near Shirland, Illinois, before emptying its own waters into the Rock River at Rockton, Illinois.

The Sugar River is a high quality stream that flows through rural lands and native grasslands in southern Wisconsin and northern Illinois. It is classified as an Exceptional Resource Water in Wisconsin and as a Resource Rich Area in Illinois because of the abundance and diversity of the wildlife its watershed supports. The Sugar, rising in the hills of southwest Wisconsin near Madison, meanders southeast, past Paoli and Belleville where it is dammed to form Lake Belleville. From there it flows east of Monticello where it is joined by the Little Sugar River and streams south through Albany, and Brodhead, into Illinois where it joins the Pecatonica River. The Sugar River’s 115 mile course is divided into Upper and Lower watersheds.  The Upper Sugar River Watershed is located in Dane County in southern Wisconsin. The Lower Sugar River Watershed extends from Albany, WI to Shirland, IL.