Published September 19, 2025 03:11PM
Midwest Road Closes Annually for a Massive Snake Crossing. Here’s How to Spot It.
Thousands of people flock to Illinois' “Snake Road” every year to view the slithering serpent crossing
Cottonmouths are one of the more common snake to participate in the biannual movement (Photo: kristianbell/Getty Images)
Forest Service Road No. 345, better known as “Snake Road,” winds for roughly two and a half miles through southern Illinois’ Shawnee National Forest, a region home to nearly 60 percent of the state’s reptile species.
And for over 50 years, it has intermittently closed to protect a massive snake crossing.
Each fall, between September 1 and October 30, and every spring, from March 15 to May 15, the U.S. Forest Service (USFS) closes the road to vehicles and bicycles. During this time, around two dozen species of snakes slither from their winter dens in high limestone cliffs to their summer feeding grounds in LaRue Swamp.
And a road divides the two habitats.
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Because the snakes aren’t traveling far, the phenomenon is more precisely called a “movement” rather than a “migration,” local wildlife biologist Mark Vukovich told the Belleville News-Democrat. “ To mitigate vehicle collisions with snakes, the road closure began in 1972 and has been an annual tradition every year since.
Today, however, the movement has become a major attraction for amateur wildlife enthusiasts and herpetologists alike.
“Thousands of people each season come here to see it, and just walk,” Vukovich said. He adds the best time to see the snakes is October, as this is when the serpents are “most active in their movement when high temperatures are around 70 to 80 degrees and the low temperatures at night hover in the 50s.”
If you’re planning a trip to Snake Road, be sure to watch where you step and manage your snake-viewing expectations.
“It’s possible you could see zero snakes on your hike, though that’s more likely if you’re moving too quickly. You can better your chances of spotting snakes by walking slowly and keeping a close eye on the grass in the center of the road, as well as both edges of the road,” said Vuckovich.
On a very active day, however, Vukovich said he’s managed to spot up to 44 different snakes in just two hours.
It’s not just a snake hotspot, either. The USFS describes this area, LaRue-Pine Hills/Otter Pond Research Natural Area (RNA), as one of the “most unique areas in the world.” It’s also home to over 1,350 species of plants and animals.
“LaRue-Pine Hills’ unique physical characteristics dictate and support a rich biodiversity not found anywhere else in the country. In all, the area covers about 4.5 square miles (3,547 acres) and contains 14 natural communities, including forests, wetland, prairie, glade, and barren ecosystems and geologic features,” writes the USFS.
In addition to snakes, the area is home to 66 percent of Illinois‘ amphibians and over 90 percent of the state’s mammals.
If you’re a snake-lover and want to visit LaRue-Pine Hills/Otter Pond RNA during the “movement,” be sure to check out the LaRue Pine Hills Snake Road group on Facebook, where over 6,000 serpent lovers offer insight on trail conditions and share snake sighting experiences. Visitor questions can be directed to “Snake Sentinels,” special volunteers trained by the USFS to collect data and identify various species crossing the road each year.
Just don’t try to pick up the snakes yourself—it’s prohibited by federal law—and be sure to watch your step. Many of the snakes that travel across the road are quite small.
By far the most common species, which accounts for over 90 percent of all sightings, is the venomous northern cottonmouth. Also known as a water moccasin, this darkly colored—usually near-black or olive brown—snake isn’t aggressive, but its bite is fatal without rapid administration of an antivenom. A cottonmouth is easily identifiable by its bright white inner mouth, which it flashes at potential predators. Cottonmouths are often patterned and born with bright yellow tail tips to attract prey, but as the snakes age, the tail tips and discernible patterns usually fade to a dull blackish color.
Other snakes seen during the biannual Snake Road movement include nonvenomous plain-bellied water snakes, rough green snakes, and Western ribbon snakes, as well as venomous species like the northern copperhead and timber rattlesnake.
