Illinois runs two trout seasons a year and lets you fish both of them before they open, which sounds like a contradiction until you read the rule: the water opens to catch-and-release a couple of weeks before it opens to harvest.
Every season we have verified in Illinois
One block per rule, because a single species can be on two calendars in the same state depending on the water. The band under each heading is the legal season; the row under it is what our own data says the fish are doing.
Trout — Inland trout waters, spring season
Harvest opens on the first Saturday in April — April 4 in 2026, April 5 in 2025 — at stocked ponds, lakes and streams across the state. Before that, a catch-and-release period runs from around the third Saturday in March: the water is open, nothing comes home. Everyone needs an inland trout stamp as well as a licence, including catch-and-release anglers, unless they are under 16, blind or disabled, or an Illinois resident on leave from active duty.
- Limit
- 5 trout a day.
Trout — Inland trout waters, autumn season
No date to look up. IDNR sets the October opening each year and publishes the site list with it.
A second stocking of around 80,000 trout supports an autumn season beginning in October, run on the same catch-and-release-then-harvest pattern. The exact date and the list of waters change year to year, so this page does not fix one.
Read on 2026-09-14 from Illinois Department of Natural Resources. Legal dates were read on the agency’s own page on the date shown beside each entry. Seasons change: the agency link is always the last word.
What the water is doing while the season is open
This is the part an agency page will not tell you. The temperature row above is the seasonal curve we use for the 3 of 13 Illinois waters we track on a prairie walleye profile, and it is why an opening date and a fishable date are not the same thing. A season that opens while the water is still in the forties is a legal invitation, not a biological one: the fish are there, they are just not eating on your schedule yet. Cross the legal band against the activity row before you book the day off.
Where to fish it
We publish a daily report for 13 Illinois waters, each with live flow or tide and today's conditions.
- Rend Lake — Franklin County
- Lake Shelbyville — Moultrie County
- Carlyle Lake — Clinton County
- Fox Chain O’Lakes — Lake County
- Lake Michigan (Chicago) — Cook County
- Shabbona Lake — DeKalb County
- Fox River — Kane County
- Cedar Lake — Jackson County
- Fox Lake — Lake County
- Clinton Lake — DeWitt County
The licence is a separate question
An open season is not permission to fish. Illinois requires a licence, and residents pay from $15.00 against $31.50 for visitors. What a Illinois licence costs and where to buy it →
Questions
When does fishing season open in Illinois?
It depends on the species: trout april 4 to december 31; trout set each year by the agency. Every date on this page was read off IDNR on 2026-09-14.
Do I need a licence to fish in Illinois?
Yes. Illinois requires a fishing licence, from $15.00 for residents. A season being open is not permission to fish: the licence is separate and so are the size and bag limits.
Are these Illinois dates going to change?
Some of them, and the page says which. Dates written as a rule in the regulations are calculated here for 2026, so they follow the rule rather than going stale. Dates the agency sets each year are shown as exactly that, with no calendar band, because inventing one would be worse than leaving it empty.