When is flathead catfish season in Illinois?

Illinois keeps flathead catfish open to fishing year-round for the 2026 regulation year — there is no closed season, though the daily bag and size limits below still apply every day.

What is the Illinois bag limit for flathead catfish?

The Illinois daily bag limit for flathead catfish is No statewide daily limit. Mississippi River: 10 flathead / day. Ohio + Wabash Rivers: no limit on fish under 35 in, only 1 flathead catfish 35 in or longer per day.. The possession limit is No statewide possession limit (site-specific waters may apply their own). Some named waters set a different limit — check the water-body overrides above.

What size flathead catfish can you keep in Illinois?

The Illinois size rule for flathead catfish is No statewide minimum. 13 in min on the Ohio + Wabash Rivers, where no more than 1 flathead catfish 35 in or longer may be kept per day.. Trophy rule: IL state-record flathead catfish 81.4 lb — Sangchris Lake (cooling lake), 2015, James Klauzer, breaking the 78 lb Carlyle Lake record set by Jody Harris in 1995. Illinois cooling lakes grow the state's heaviest flatheads; the Ohio + Wabash Rivers cap the daily harvest at 1 flathead 35 in or longer..

Do you need a license to fish for flathead catfish in Illinois?

Yes. Illinois requires a valid fishing license to fish for flathead catfish, with the usual exemptions for young children, state free-fishing days, and some senior or disabled-veteran categories. A license is valid only in the state that issued it, so non-residents need a Illinois license — compare resident and non-resident Illinois fees on the state regulations page below.

Are there gear restrictions for flathead catfish in Illinois?

Yes. In Illinois, flathead catfish fishing carries these gear rules: Hook-and-line; trotlines, setlines, limblines + juglines permitted for catfish under IDNR tag/labeling rules; Live + cut bait most effective — flatheads ambush from woody cover + deep river holes; No statewide harvest or size limit — site-specific regulations apply on listed waters only; Mississippi River: 10 flathead / day; Ohio + Wabash Rivers: 13 in min, 1 flathead ≥ 35 in / day (trophy cap); Illinois sport fishing licence required ages 16+ ($15 res / $31.50 NR annual).

Do specific Illinois waters have different flathead catfish rules?

Yes. 5 named Illinois waters carry rules that override the statewide flathead catfish regulation, including Mississippi River, Ohio River, Wabash River, and 2 more. See the named water-body overrides above for the exact rule on each.

2026 regulation year

Illinois Flathead catfish 2026 — Season, Bag Limit, Size Rules

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Last updated May 30, 2026

Flathead catfish are native to Illinois's larger rivers — the Mississippi, Ohio, Wabash, Illinois, Kaskaskia, and Rock river systems — and an ambush predator that holds around woody cover and deep holes and takes live bait. The two biggest IL flatheads on record both came from power-plant cooling lakes: James Klauzer's 81.4 lb state record from Sangchris Lake in 2015 broke the 78 lb record Jody Harris set on Carlyle Lake in 1995, both lakes whose thermal discharge fuels year-round growth. Statewide, Illinois sets no harvest or size limit on catfish; the rules live on named waters. The Mississippi River allows 10 flathead / day (the interstate Upper Mississippi River uniform regulation), while the Ohio + Wabash boundary rivers carry a 13-inch minimum and a 1-fish-35-inch-or-longer daily trophy cap matching Kentucky's and Indiana's Ohio River rules under joint Ohio River Fisheries Management Team coordination.

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Season

Open year-round Open year-round statewide. No statewide harvest or size limit on catfish. Mississippi River: 10 flathead / day. Ohio + Wabash Rivers: 13-inch minimum, no limit on fish under 35 in, only 1 flathead catfish 35 in or longer per day. A few inland lakes set their own flathead limits.

Bag & possession

Daily bag: No statewide daily limit. Mississippi River: 10 flathead / day. Ohio + Wabash Rivers: no limit on fish under 35 in, only 1 flathead catfish 35 in or longer per day.
Possession: No statewide possession limit (site-specific waters may apply their own)

Size, slot, trophy rules

Size: No statewide minimum. 13 in min on the Ohio + Wabash Rivers, where no more than 1 flathead catfish 35 in or longer may be kept per day.
Trophy rule: IL state-record flathead catfish 81.4 lb — Sangchris Lake (cooling lake), 2015, James Klauzer, breaking the 78 lb Carlyle Lake record set by Jody Harris in 1995. Illinois cooling lakes grow the state's heaviest flatheads; the Ohio + Wabash Rivers cap the daily harvest at 1 flathead 35 in or longer.

Gear restrictions

Hook-and-line; trotlines, setlines, limblines + juglines permitted for catfish under IDNR tag/labeling rules
Live + cut bait most effective — flatheads ambush from woody cover + deep river holes
No statewide harvest or size limit — site-specific regulations apply on listed waters only
Mississippi River: 10 flathead / day; Ohio + Wabash Rivers: 13 in min, 1 flathead ≥ 35 in / day (trophy cap)
Illinois sport fishing licence required ages 16+ ($15 res / $31.50 NR annual)

Named water-body overrides

Where statewide rules differ on specific Illinois waters:

Mississippi River
10 flathead / day (interstate Upper Mississippi River uniform regulation); IL ↔ IA + IL ↔ MO reciprocal main stem
Ohio River
13 in min, no limit under 35 in, 1 flathead ≥ 35 in / day; IL/KY boundary under the Ohio River Reciprocity Compact
Wabash River
13 in min, no limit under 35 in, 1 flathead ≥ 35 in / day; IL/IN boundary water
Lake Sangchris
No statewide limit on flathead catfish; cooling lake — IL state-record flathead 81.4 lb (2015)
Carlyle Lake
No statewide limit on flathead catfish; former IL state-record flathead 78 lb (1995)

Official source

Illinois Department of Natural Resources publishes the authoritative 2026 Illinoisfishing regulations. Always verify the current rule before fishing — emergency closures and in-season changes can override what's published here.

The flathead catfish rules on this page are sourced from Illinois Department of Natural Resources's official flathead catfish regulation page.

Visit official Illinois fishing regulations →

Emergency-order channel

Flathead catfish closures, slot-limit changes, and harvest pauses are posted to Illinois Department of Natural Resources's emergency-order feed — check it before any Illinois trip during the active season.

Frequently asked questions

When is flathead catfish season in Illinois?: Illinois keeps flathead catfish open to fishing year-round for the 2026 regulation year — there is no closed season, though the daily bag and size limits below still apply every day.
What is the Illinois bag limit for flathead catfish?: The Illinois daily bag limit for flathead catfish is No statewide daily limit. Mississippi River: 10 flathead / day. Ohio + Wabash Rivers: no limit on fish under 35 in, only 1 flathead catfish 35 in or longer per day.. The possession limit is No statewide possession limit (site-specific waters may apply their own). Some named waters set a different limit — check the water-body overrides above.
What size flathead catfish can you keep in Illinois?: The Illinois size rule for flathead catfish is No statewide minimum. 13 in min on the Ohio + Wabash Rivers, where no more than 1 flathead catfish 35 in or longer may be kept per day.. Trophy rule: IL state-record flathead catfish 81.4 lb — Sangchris Lake (cooling lake), 2015, James Klauzer, breaking the 78 lb Carlyle Lake record set by Jody Harris in 1995. Illinois cooling lakes grow the state's heaviest flatheads; the Ohio + Wabash Rivers cap the daily harvest at 1 flathead 35 in or longer..
Do you need a license to fish for flathead catfish in Illinois?: Yes. Illinois requires a valid fishing license to fish for flathead catfish, with the usual exemptions for young children, state free-fishing days, and some senior or disabled-veteran categories. A license is valid only in the state that issued it, so non-residents need a Illinois license — compare resident and non-resident Illinois fees on the state regulations page below.
Are there gear restrictions for flathead catfish in Illinois?: Yes. In Illinois, flathead catfish fishing carries these gear rules: Hook-and-line; trotlines, setlines, limblines + juglines permitted for catfish under IDNR tag/labeling rules; Live + cut bait most effective — flatheads ambush from woody cover + deep river holes; No statewide harvest or size limit — site-specific regulations apply on listed waters only; Mississippi River: 10 flathead / day; Ohio + Wabash Rivers: 13 in min, 1 flathead ≥ 35 in / day (trophy cap); Illinois sport fishing licence required ages 16+ ($15 res / $31.50 NR annual).
Do specific Illinois waters have different flathead catfish rules?: Yes. 5 named Illinois waters carry rules that override the statewide flathead catfish regulation, including Mississippi River, Ohio River, Wabash River, and 2 more. See the named water-body overrides above for the exact rule on each.

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