The Sugar River is a tributary of the Pecatonica River, approximately 100 mi (160 km) long, in the U.S. states of Wisconsin and Illinois.
It rises in the hills of southwest Wisconsin, in southwest Dane County, approximately 15 mi (25 km) southwest of Madison. It meanders southeast, past Paoli and Belleville where it is dammed to form Lake Bellview. From there it meanders east of Monticello where it is joined by the Little Sugar River and flows south through Albany, and Brodhead. It crosses into northern Illinois flowing past an extensive area of the Winnebago County Forest Preserve system. These preserves are Sugar River Alder, Colored Sands, and Sugar River. The river joins the Pecatonica River in northern Winnebago County, approximately 5 mi (8 km) south of the state line and approximately 15 mi (25 km) NNE of Rockford.
The Yellow Creek watershed encompasses about 140,000 acres primarily in Stephenson County. Yellow Creek is just one of about twenty streams that feed into the Pecatonica River. In it's turn, the Pecatonica joins the Sugar River near Shirland, Illinois and both feed into Rock River at Rockton Illinois. Sugar River and the Pecatonica River are both considered "navigable" streams, Yellow Creek is not. Yellow Creek flows through the popular Krape Park in Freeport as well as Hidaway Park in Pearl City.
The Sugar is an excellent stream for the fisherman who wants little of development and other people. The logjams and sand bottom provide excellent fish habitat. The channel catfish and smallmouth bass are the most common game fish. However, an occasional walleye or northern pike will be taken near tributary mouths and at the mouth where the Sugar joins the Pec. Carp can be taken in the slow muddy areas near road crossings. Occasionally, bluegills and crappies will be found in the side channels and backwaters where there is little water movement.
Because public access is limited to two forest preserves and only two bridges, the Sugar is not the place for the canoeist demanding easy access and continuous comfort areas. When the water level is low, portages should be expected over sandbars and logjams. The most popular canoe trip requires launching at Avon, canoeing to Sugar River Forest Preserve, camping for the night and then canoeing to the mouth near Shirland. Canoes may also be launched at Colored Sands Forest Preserve or Yale Bridge Road.
Users of the Sugar River may expect to find nature at its wildest. However, it is important to realize this may mean poison ivy antidotes and mosquito repellants which are a must in the summer.
Channels, logjams, shoreline, tributaries.
Walleye or northern pike will be taken near tributary mouths and at the mouth where the Sugar joins the Pec. Carp can be taken in the slow muddy areas near road crossings. Occasionally, bluegills and crappies will be found in the side channels and backwaters where there is little water movement.