Black Snakes in Illinois

Written by Brandi Allred
Updated: June 13, 2023
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Key Points:

  • There are 40 species of snakes found in Illinois.
  • The black racer snake is one of them.
  • The 40 different species range in size from just over a foot long to well over six feet.

There are 40 species of snakes currently recognized in Illinois. Of those 40 species, 11 are listed as threatened or endangered. But what about black snakes in Illinois? There are actually seven species of black snakes in Illinois. Like all snakes, these species are cold-blooded and rely on the sun’s warmth to warm their bodies.

They range in size from just over a foot long to well over six feet. While none of the black snakes in Illinois have venom, they’re still wild animals and should be respected and left alone.

Let’s take a closer look at the seven species of black snakes in Illinois. Then, we’ll discuss what you should do if you come across a snake in Illinois.

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7. Black Racer (Coluber constrictor)

southern black racer slithering through brush

Black racers are one of the few black snakes in Indiana to be almost entirely black.

© Shots

Black racers grow up to five feet long and have slender, thin bodies. They’re common throughout the entire eastern half of the United States and even live in Florida.

Black racers are sometimes mistaken for black rat snakes or black kingsnakes. They’re almost entirely black or dark gray, with the exception of some white coloring at the throat. Juvenile black racers actually aren’t black snakes in Illinois—they’re light gray with brown patterning.

Black racer snakes live anywhere they can find food. Their favorite prey is birds, rodents, lizards, snakes, and even insects.

6. Ringneck Snake (Diadophis punctatus)

Ringneck Snake (Diadophis punctatus)

Ringneck snakes may be small, but they are common throughout most of the eastern United States.

©Tom Fenske/

Ringneck snakes range in color from gray to black, with yellow to tan bellies. They’re one of the black snakes in Illinois. But, as you might have guessed, they get their name from the brightly colored ring around their neck. Ringneck snakes have yellow bands just behind their heads, but other than that, their backs are all black or gray. 

These snakes are so small you might never notice them, with the biggest reaching only 15 inches long. They live just about anywhere they can find small prey, including forests, rocky hillsides, grasslands, or riverine environments. They’re not a threat to humans, though they use weak venom for hunting prey like mice and lizards.

5. Western Mud Snake (Farancia abacura)

mud snake

One of the largest black snakes in Illinois, the western mud snake can grow to over six feet long.


Western mud snakes live throughout the southeastern United States. They’re found only in the extreme southern part of Illinois. Mud snakes spend most of their time in the water, either in swamps, slow-moving rivers, lakes, wetlands, or ponds. They prefer areas with lots of aquatic plant life to hide in; humans rarely get the chance to see these beautiful, elusive snakes.

Western mud snakes are one of the black snakes in Illinois, but they’re not entirely black. Both adults and juveniles have all-black backs, with red to pink bellies and sides. Young mud snakes have bright red, striped bellies, while adults tend more towards pink. These snakes eat mostly amphibians, like salamanders, frogs, toads, and tadpoles.

4. Kingsnake (Lampropeltis getula)

Snakes in Mississippi - Eastern Black Kingsnake (Lampropeltis nigra)

One of the prettiest black snakes in Illinois, the kingsnake is one of several subspecies.

©Matt Jeppson/

Kingsnakes grow to an average length of 3-4 feet. They’re almost entirely black, except for thin, white bands that run down their bodies. They prefer living in grasslands, shrublands, or areas bordering wetlands or streams. Kingsnakes aren’t venomous, but that doesn’t stop them from consuming other venomous snakes.

These snakes only occupy the southern half of Illinois. They’re sometimes mistaken for other black snakes in Illinois. But, only the black kingsnake bears the distinctive pale bands around its body.

3. Black Rat Snake (Pantherophis obsoletus)

An adult rat black snake peaks over a rock

Reaching a length of up to 6 feet, black rat snakes are one of the longest snakes in Illinois.

©Matt Jeppson/

One of the larger black snakes in Illinois, black rat snakes grow up to six feet long. But don’t be afraid of them—they’re not venomous and have no interest in biting humans. Instead, as you might have guessed from their name, they prey mainly on rodents, like rats and mice. 

Black rat snakes live throughout the entire eastern United States. In Illinois, they prefer forests, floodplains, and the margins of suburban areas.

2. Graham’s Crayfish Snake (Regina grahamii)

Graham’s Crayfish Snake

Graham’s crayfish snakes have a very specific diet that relies heavily on one species.

©Rusty Dodson/

Graham’s crayfish snakes range in color from dull brown to gray to black. They’re two-toned, with copper or tan-colored bellies and solid backs and sides. These snakes don’t grow quite as big as other black snakes in Illinois, maxing out at around two feet long. 

Graham’s crayfish snakes are semi-aquatic and live in brackish ponds, lakes, or slow-moving streams. They get their name from their primary food source, the crayfish. Unlike other snakes that eat a variety of foods, Graham’s crayfish snakes eat almost entirely crayfish.

1. Northern Red-bellied Snake (Storeria occipitomaculata)

red bellied snake Storeria occipitomaculata in defensive posture showing underside

Red-bellied snakes are cousins to Dekay’s brownsnakes.

©Kevin Collison/

Northern red-bellied snakes are one of the smallest black snakes in Illinois at around 10 inches fully grown. They’re solidly colored, but aren’t always black — these snakes are more often dark brown with bright red bellies and brown bands just behind their head. They live only in parts of southern Illinois and tend to stick to wetlands or open fields. However, northern red-bellied snakes are also comfortable living in suburban zones.

These snakes are so small that their diet consists mainly of insects like slugs. They’re completely harmless and common to many parts of the eastern United States.

What to Do if You See a Black Snake in Illinois

As with all wild animals, if you see a black snake in Illinois, stay calm, and leave it alone. These snakes are harmless but will bite to defend themselves.

Other Reptiles Found in Illinois

Box Turtle

Unlike many other species in the turtle family, eastern box turtles are terrestrial.


In addition to snakes, there are numerous other reptiles found in the state of Illinois. These reptiles include lizards, turtles, and other species. Some of these reptiles are common and can be easily spotted in the wild, while others are rare and may require a bit of luck to come across.

Here is a short list of other reptiles found in Illinois:

Summary of Black Snakes in Illinois

1Northern Red-bellied Snake
2Graham’s Crayfish Snake
3Black Rat Snake
4Black Kingsnake
5Western Mud Snake
6Ringneck Snake
7Black Racer

The photo featured at the top of this post is © Breck P. Kent/

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About the Author

Brandi is a professional writer by day and a fiction writer by night. Her nonfiction work focuses on animals, nature, and conservation. She holds degrees in English and Anthropology, and spends her free time writing horror, scifi, and fantasy stories.

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