Rock River - Sterling Pool
Info / Counties: Lee, Whiteside
Family Friendly
Yes
Handicap Access
No
Boat Fishing
Yes
Boat Ramps
Yes
Boat Rentals
No
Camping
No
Picnicking
No
Skiing
No
Swimming
No
Trout Stocking
No
Zebra Mussels
None
Location 2106 acres
The Rock River arises in Washington County, Wisconsin and enters Illinois near Rockton, IL. It flows in a general southwesterly direction for approximately 165 miles before entering the Mississippi River near Rock Island, IL. The river drains 10,280 square miles, with about ½ of this area in Illinois. After the confluence with the Pecatonica River near Rockton, the Rock River is a 7th order stream.
The Illinois portion of the river has major population centers at Rockford, Byron, Oregon, Dixon, Sterling/Rock Falls, and Rock Island. The remainder of the Illinois portion of the basin is primarily agricultural. Three major tributaries enter the Rock River in Illinois: 1) The Pecatonica River with a drainage area of 2,641 square miles enters the Rock River near Rockton, 2) the Kishwaukee River with a drainage area of 1,257 miles enters just south of Rockford, and 3) the Green River with a drainage area of 1,131 square miles enters the Rock River almost at the mouth of the river near the Quad Cities. The main-stem has low-head dams at Rockton, Rockford, Oregon, Dixon, 2 at Sterling/ Rock Falls, and a split dam at Milan.
IDNR Fisheries uses designated pool sections formed by these low-head dams as a descriptive function and as a fish management unit. Each of these designated pool sections have their own unique habitat and water quality features that affect the fishery within these pools. The connectivity for the fish populations in the Rock River allows for unlimited downstream emigration with very limited upstream immigration over these low-head dams.
Contact
IDNR Region 1 Streams Biologist
Jubilee College State Park 13921 West Route 150 Brimfield, IL 61517
Send Message
309-370-5296
Description
The Sterling Pool section (RRS). The Sterling Pool section is approximately 15 river miles in length (2,106 surface acres) from the Lower Dam in Sterling to the Dixon Dam in Dixon, Illinois. The small tributary streams that enter this section are Howland Creek, Threemile Branch Creek, and Plum Creek.
Fishery History
The Rock River was sampled each fall from 2020 through 2025 by the Illinois Department of Natural Resources (IDNR) Region 1 Fisheries crew. The purpose was to collect and evaluate the sport fish populations in the Illinois section of the Rock River. State endangered and State threatened fish species were also collected and documented with the surveys.
Sterling Pool section (RRS):
Black Crappie – Black Crappie were collected in 3 of the 6 survey years in this section at a collection rate of 7 fish per hour. These fish ranged from 7 to 12 inches in length.
Bluegill - Bluegill were collected in 4 of the 6 survey years from this section with an average collection rate of 19 fish per hour. These ranged from 1 to 8 inches in length.
Channel Catfish - Channel Catfish were collected in every survey from this section with an average collection rate of 27 fish per hour and a total of 175 fish. These fish ranged in size from 12 to 29 inches with 56% of stock size fish over 18 inches in length. The body condition rating was average with average Wr values over 88.
Flathead Catfish – Flathead Catfish are not effectively sampled during cold water boat electrofishing surveys. Hoop net or warm water boat electrofishing surveys will be utilized in the future to evaluate the Rock River Flathead Catfish population.
Largemouth Bass – Largemouth Bass were collected in 5 out of 6 survey years from this section with a low collection rate of 11 fish per hour. These fish ranged in size from 4 to 14 inches in length. A low-density Largemouth Bass population is present in the Rock River. The rocky habitat and stream flow favors the Smallmouth Bass population.
Muskellunge - No Muskellunge were sampled in this section during any of the survey years. A low-density Muskellunge population is found in the Rock River from fish that have escaped from stocked lakes in the watershed.
Northern Pike – No Northern Pike have been sampled in this section in any of the survey years. A low-density Northern Pike population is found in the Rock River and is supported by natural reproduction.
Rock Bass – Rock Bass have only been sampled in this section in the 2021 survey year. This fish was 7 inches in length. A low-density Rock Bass population is found in the Rock River and is supported by natural reproduction.
Sauger – Sauger were collected in every survey from this section with an average collection rate of 2 fish per hour and a total of 20 fish. These fish ranged in size from 11 to 18 inches with 46% of stock size fish over 15 inches in length. The body condition rating was good with the average Wr values over 90. A low-density Sauger population is found in the Rock River and is supported by natural reproduction.
Smallmouth Bass – Smallmouth Bass were collected in every survey from this section with an average collection rate of 48 fish per hour and a total of 392 fish. These fish ranged in size from 2 to 18 inches with 22% of stock size fish over 14 inches in length, 1% over 17 inches in length. The body condition rating was good with the average Wr values over 90, but 2022 and 2024 averages in the mid 80’s. A high-density Smallmouth Bass population is found in the Rock River and is supported by natural reproduction.
Walleye – Walleye were collected in every survey from this section with an average collection rate of 23 fish per hour and a total of 133 fish. These fish ranged in size from 2 to 24 inches with 68% of the stock size fish over 15 inches in length, 35% over 18 inches in length. The body condition rating was good with the average Wr values over 90. A moderate-density Walleye population is found in the Rock River and is supported by stocking and natural reproduction.
White Bass – White Bass were collected in 5 of 6 survey years from this section at an average low collection rate of 7 fish per hour. These fish ranged from 8 to 13 inches in length.
White Crappie – White Crappie were collected in 1 of the 6 survey years in this section at a low collection rate of .1 fish per hour. These fish ranged from 9 to 10 inches in length.
Yellow Perch - Yellow Perch were collected in 4 of the 6 survey years in this section at a low collection rate of 4 fish per hour. These fish ranged from 4 to 8 inches in length.
Site Regulations
Rock River Fishing Regulations as of 2026:
From the Wisconsin State Line downstream to the Confluence with the Mississippi River, including tributaries:
Smallmouth Bass: 14-inch minimum Length Limit with a daily harvest limit of 3 fish. All Smallmouth Bass must be immediately released between April 1 and June 15th.
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