State herp calendar
Reptiles and Amphibians of Illinois
Illinois is mostly farmland, with river bluffs and forest in the south. American Toads and Painted Turtles are the most-reported herps. Snakes are the biggest group. April is the busiest month. The Northern Cottonmouth, Eastern Copperhead and Timber Rattlesnake live here.
62 species3 ecoregions3 venomous
Search entire stateSpecies out across Illinois, by group and month
| Group | ||||||||||||
|---|---|---|---|---|---|---|---|---|---|---|---|---|
| Snakes | 7 | 16 | 25 | 25 | 20 | 17 | 18 | 21 | 20 | 12 | 3 | |
| Lizards | 3 | 5 | 5 | 5 | 4 | 4 | 4 | 3 | 1 | |||
| Turtles | 1 | 3 | 6 | 7 | 7 | 7 | 7 | 6 | 7 | 5 | 2 | 1 |
| Frogs and Toads | 1 | 9 | 10 | 12 | 11 | 9 | 10 | 9 | 12 | 12 | 10 | 3 |
| Salamanders | 2 | 9 | 11 | 11 | 7 | 1 | 9 | 10 | 9 | 1 |
Numbers = species active that month (at peak or just starting / winding down).
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Hi, I'm Nick. I built Herp Calendar on my own and I keep it free, with no ads. If it has helped you find a herp this season, a small tip goes straight into the hosting and the data work. Only if you can spare it. Either way, I'm glad you're here.
Pick your ecoregion
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Tap a region to see what's out
Ecoregions of Illinois
Seasons shift a lot between Illinois's ecoregions. Pick the one nearest you for a 12-month calendar of what's out.
Corn Belt Midwest
37 speciesFarm country with ponds and parks full of toads, painted turtles and garter snakes.
View calendar →Interior Low Plateaus
63 speciesRolling hills, caves and streams with toads, ratsnakes and pond sliders.
View calendar →Upper Midwest Hardwood Forests
27 speciesHardwood forest and farm ponds with toads, painted turtles and leopard frogs.
View calendar →Venomous here: Eastern Copperhead, Northern Cottonmouth, Timber Rattlesnake. Don't handle any snake you can't identify.
About Illinois
When are reptiles and amphibians most active in Illinois?
April is the busiest month in Illinois, with 48 species at peak activity. At least half of the area's species are active from March through November.
What reptiles and amphibians live in Illinois?
62 species have enough iNaturalist records to show here: 25 snakes, 14 frogs and toads, 11 salamanders, 7 turtles, and 5 lizards. The most-reported are the American Toad, Painted Turtle, and Pond Slider.
Are there venomous snakes in Illinois?
Yes. The Northern Cottonmouth, Eastern Copperhead, and Timber Rattlesnake live here. Don't handle them.
Where does this data come from?
Activity calendars are built from iNaturalist research-grade observations (downloaded through GBIF, September 2026), corrected for how many people are out observing each month. Rare and protected species are left off on purpose.