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Pecatonica River

Description: The Pecatonica River is approximately 92 miles long in Illinois and drains 805 square miles. The total drainage area of the basin, including the Wisconsin portion of the stream, is 2,641 square miles.

Location: The Pecatonica River originates in Wisconsin and enters Illinois in Stephenson County just north of Winslow. It flows in a southeasterly direction through eastern Stephenson County and western Winnebago County and enters the Rock River near Rockton.

History and Status of the Sport Fishery: There are more than 70 species of fish in the Pecatonica River Basin, including several species of sport fish. The most sought after of the sport fish are the walleye and channel catfish, with channel catfish being the most abundant. Largemouth and smallmouth bass fishing are also popular. The Upper Rock River and Lower Pecatonica River are stocked each year with close to 70,000 walleye to support an excellent trophy fishery for this species. Panfish such as bluegill and crappie can be found in some areas, along with the occasional northern pike.

Fishing Outlook  ( Full PDF Report )

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Fish Status


Very Good

Catfish are abundant throughout the Pecatonica River and in the Sugar River, a tributary of the Pecatonica River near the Wisconsin border. An electrofishing survey done in 2017 found a catch rate of .3 fish/minute near the mouth of the river near Macktown Forest Preserve, but lower in other areas of the river. A hoop net survey from 2014 found that the average weight of collected fish was approximately 1.8 pounds, with the largest fish (3 and 4 pounds) collected near the town of Pecatonica and upstream near Winslow. The Sugar River also yielded several fish in the 4 pound range. The average size of the adult fish was 14" with 80% over 12" in length, and 29% of these were over 16", which bodes well for fishermen looking for quality fish. Flathead catfish were most abundant near Winslow, with the largest flathead catfish weighing 16.5 pounds.



Smallmouth bass are most common in the lower Pecatonica River near the confluence with the Rock River around rip rapped areas, and further upstream in a few of the larger tributaries. A survey conducted in the summer of 2017 found small numbers of adult fish below the Krape Park dam in Yellow Creek, and in the Pecatonica River near Macktown Forest Preserve near Rockton, IL. However, the catch rate near Macktown was low (0.2 smallmouth bass/minute). The best fishing area for smallmouth bass is near the mouth of the river north of Rockford.


Very Good

Walleye are stocked each year into the lower Pecatonica River and the upper Rock River to provide a quality sport fishery for this species. Fishing is generally good near the mouth of the Pecatonica River north of Rockford, and occasionally at the mouths of the tributaries, especially Yellow Creek. Walleye ranging in size up to and over the state record weight have been caught in recent years, and fishermen regularly report catching memorable size walleye from the lower Pecatonica River.

Fishing Regulations: *Consult the current Illinois Fishing Regulations Booklet for more detailed information.


Creel Limit

Minimum Length Limit

Black Bass (Largemouth, Smallmouth) Entire river including tributaries in State of Illinois.

6 singly or in combination with no more than 3 smallmouth bass in the daily creel

14" for Smallmouth Bass

Walleye, Sauger, or Hybrid Walleye Wisconsin state line downstream to the Sears and Steel dams at Milan

6 either singly or in combination

14"minimum length limit

Walleye, Sauger, or Hybrid Walleye Sears and Steel dams downstream to confluence with Mississippi River, State of Illinois (Rock Island County).

6 fish daily creel with no more than 1 walleye greater than 27" in total length

15" minimum length limit with a 20-27" protected Slot Length Limit.

Northern Pike

3 fish daily creel

24" minimum length limit

Note: There is a closed season on smallmouth bass. All smallmouth bass caught between April 1 and June 15 must be immediately released alive and in good condition back into the waters from which they came.

There were 1 tournaments held on this waterbody in 2023.

Species Total Fish Caught
Channel Catfish 12
Flathead Catfish 11