Every snake on this list is slithering somewhere in the U.S. right now.
Snake bites are way more common than most people think, and if it happens to you, it is probably from one of these. This list covers every venomous snake species found in the United States. Some are aggressive, others just want to be left alone, but they all have one thing in common—they are responsible for the majority of venom-related ER visits every year. These aren’t international monsters. These are your backyard villains.
1. Copperheads are the kings of blending in and biting when stepped on.
Copperheads love to hang out where leaf piles and trail edges meet, which makes them dangerously easy to miss until it is too late, according to Jessie Szalay at Live Science. Found across the eastern and southern U.S., especially in states like North Carolina, Georgia, and parts of Texas, they are responsible for more bites than any other snake in the country. Not because they are aggressive, but because people literally walk into them.
Their bite hurts, a lot, but it is rarely fatal. That said, their venom causes tissue damage, swelling, and some gnarly bruising. Most people get bit on the ankle or hand, usually while hiking or doing yard work. And since they do not rattle or hiss much before striking, there is barely a warning. If you are in copperhead country, watching where you step is not just smart, it is survival.
2. Cottonmouths do not bluff for long once they show that white mouth.
You might know them as water moccasins, but whatever you call them, cottonmouths are one of the boldest snakes in the U.S., as reported by Jamie Burchill at Outdoor Alabama. Found mostly in the Southeast, especially around swamps, rivers, and lakes in Florida, Alabama, and Mississippi, they are not shy about holding their ground. That open white mouth display is their signature threat, and if you ignore it, things escalate fast.
They swim with their heads above water and will even climb into low-hanging trees, which is something nobody asked for. Cottonmouth venom is cytotoxic, meaning it eats away at tissue. The pain is intense, and the recovery can take weeks if not months. If you are wading through murky water in the South, there is a decent chance one is nearby whether you see it or not.
3. Eastern Diamondback Rattlesnakes can hit you with the strongest venom dose in the country.
The eastern diamondback is not just big, as stated by the experts at the Smithsonian’s National Zoo. It is massive. These snakes regularly hit five to six feet long and are built like a coiled muscle. Found across the Southeastern U.S., especially in Florida, Georgia, and the Carolinas, they love open pine forests and overgrown fields. If they rattle, listen. You do not get many second chances with this one.
Their venom is a brutal mix of hemotoxins that can cause internal bleeding, tissue death, and in rare cases, death. They are responsible for fewer bites than copperheads only because they usually give plenty of warning and are a little more reclusive. But when they bite, it is serious. This is not a dry warning snap. They mean business.
4. Timber Rattlesnakes are out there quietly minding their business until they are not.
Timber rattlesnakes are the quiet introverts of the venomous snake world, according to John Rafferty at Britannica. Found all across the eastern U.S. and stretching into parts of the Midwest, they are surprisingly chill unless provoked. Think dense woods, rocky outcrops, and the kinds of hiking trails where no one has been in a while. That is their zone.
What makes them dangerous is their ability to stay absolutely still until you are right on top of them. They rely on camouflage and calm, but once cornered or stepped on, their strike is fast and accurate. Their venom isn’t as toxic as the eastern diamondback, but it is still dangerous and can cause systemic effects if not treated. They are quiet until they are not, and then it is a whole different vibe.
5. Mojave Rattlesnakes bring the most neurotoxic venom in the country to the desert party.
Living in the dry southwestern deserts from California to New Mexico, the Mojave rattlesnake doesn’t need size to scare you. Its venom is an overachiever. Unlike other rattlesnakes that mostly rely on hemotoxins, Mojaves come packed with a neurotoxin that hits your nerves and breathing before you even process the pain.
What makes them extra tricky is how similar they look to western diamondbacks. People misidentify them constantly. But Mojaves are twitchier, more prone to biting, and less predictable in general. They have a pretty chill look, but that is exactly what makes them so dangerous. They are the “don’t judge a book by its cover” of the reptile world.
6. Western Diamondbacks are the reason everyone checks their boots in Texas.
This is the snake that shows up in movies, cowboy legends, and unfortunately, a ton of real ER records. Western diamondbacks live all over the southwestern U.S., from Texas through Arizona and into parts of California. They are huge, loud, and unapologetically present wherever dry land meets brush or rock.
Their venom isn’t the most toxic, but they make up for it with volume and aggression. They strike fast and do not always give a full rattle before they hit. These are the snakes found under decks, near sheds, and on dusty trails. If you are in the desert or ranch zones, they are basically part of the ecosystem whether you like it or not.
7. Pygmy Rattlesnakes are small but still put plenty of people in the hospital.
These little snakes are easy to miss, which is exactly the problem. Found in the southeastern states, especially Florida and South Carolina, pygmy rattlesnakes rarely get longer than two feet. But their venom can still cause serious medical issues, especially for kids or small pets that stumble into them.
They tend to hang out in brushy areas, forest floors, and sometimes even suburban yards. Their rattle is more of a buzz and is hard to hear unless you are really close. Most bites happen when someone steps too close without seeing them, and the swelling and pain afterward are way more than you’d expect from such a tiny body.
8. Prairie Rattlesnakes hold down the Great Plains like they own the place.
From the Dakotas to Colorado and even parts of Utah and Wyoming, prairie rattlesnakes are the venomous ambassadors of open range country. They are fast, relatively aggressive, and not afraid to bite when they feel cornered. Ranchers and hikers run into them more than they would like to admit.
Their venom is a solid mix of hemotoxins that can break down tissue and cause internal bleeding, but what really gets people is how quickly they strike. Prairie rattlers don’t do a lot of warning. They coil, they launch, and it is done. They love sun-warmed rocks and tall grass, which makes them easy to miss until you are too close for comfort.
9. Sidewinders basically throw themselves at you in the desert and then vanish.
Sidewinders are the weirdos of the rattlesnake world. Found mostly in sandy deserts like southeastern California, Nevada, and Arizona, they move with that signature sideways shimmy that looks broken but is terrifyingly effective. Their whole vibe is sneak attack energy. They are fast, oddly graceful, and really good at disappearing into dunes.
They are not massive, but they do pack a venomous punch. The danger with sidewinders isn’t just the venom—it is the speed. They strike quick, then they are gone, which makes it harder to figure out what just hit you. Most bites happen to people who are out exploring desert trails or messing with off-road gear. They like the heat, they like the open sand, and they do not care that you did not see them coming.
10. Arizona Black Rattlesnakes are masters of drama with color and mood swings.
You want a snake with personality issues? The Arizona black rattlesnake can literally change color depending on its environment and emotional state. Found in central and southeastern Arizona, these snakes hang out in oak forests, grasslands, and rocky mountain zones. They are introverted by nature, but when provoked, they bring the heat.
They’re not the largest, but they’re bold. Their venom is strong enough to cause necrosis and muscle damage, and they are not above biting if surprised or messed with. Hikers run into them more than anyone else, especially near trails in places like the Santa Catalina Mountains. If a snake shifts shades in front of you like it is trying on outfits, it is probably time to back up.
11. Red Diamond Rattlesnakes bring west coast vibes with desert power.
Think of the red diamond rattlesnake as the California cousin to the western diamondback. It lives mostly in southern California and Baja, loves dry scrublands and rocky canyons, and gets its name from the reddish tint in its scales. They are not the most aggressive species, but they have the same muscle-packed body and a solid venom load that means business.
These snakes usually give you some warning. They rattle, they posture, and most will try to get away unless they feel trapped. The issue is that hikers and mountain bikers in places like San Diego County often surprise them, and once that happens, it is game on. Their venom causes intense swelling and pain, and while fatalities are rare, they can absolutely ruin your week.
12. Southern Pacific Rattlesnakes have evolved venom that adapts depending on location.
This snake deserves a sci-fi documentary. Found in southern California, from the coast to the inland foothills, the southern Pacific rattlesnake has different venom profiles depending on where it lives. Some produce neurotoxic venom similar to the Mojave rattlesnake. Others have more classic hemotoxic venom. It is basically a choose-your-own-nightmare situation.
They blend in well with the dusty terrain and don’t always rattle before striking. That unpredictable nature, both in behavior and venom makeup, makes them especially dangerous to outdoor workers and hikers in areas like the Santa Monica Mountains or parts of Orange County. You think you are dealing with a regular bite, but the symptoms hit differently depending on the zip code.
13. Eastern Coral Snakes are shy but sneakily dangerous with their neurotoxic venom.
Coral snakes are not common biters, but when they do strike, things get intense fast. Found mostly in the southeastern U.S.—think Florida, southern Georgia, and parts of Alabama—these snakes are flashy with their red, yellow, and black banding, but their real danger is internal. Their venom is a pure neurotoxin that can cause respiratory failure if left untreated.
The good news is they have tiny fangs and short reach. The bad news is the venom acts on your nervous system, not just the bite site. Symptoms can be delayed, which tricks people into thinking they are fine, until they are not. Most bites happen when someone mistakes them for the harmless scarlet kingsnake. You have to really look close to tell the difference, and sometimes people do not until it is too late.
14. Texas Coral Snakes rarely mess around but when they do, it is serious.
A cousin of the eastern coral snake, the Texas coral snake lives up to its name by showing up across the Lone Star State and into parts of Louisiana and Arkansas. They are secretive, nocturnal, and not fans of confrontation. Still, every year a few people pick them up, corner them, or accidentally brush against one while reaching into brush piles, and the result is not fun.
They look small and harmless, but the neurotoxic venom can mess with your body’s ability to breathe. It works slower than a rattlesnake bite, but once it kicks in, it needs antivenom quickly. These snakes are gorgeous, but they do not belong in your hands, your bag, or your curiosity zone. Treat them like a live wire that just happens to slither.
15. Rock Rattlesnakes bring serious danger to high elevations and rocky cliffs.
This is not a snake you are going to run into by accident unless you are hiking above 6,000 feet in places like west Texas or southern New Mexico. Rock rattlesnakes are high-altitude pros that love steep, rocky habitats and tend to freeze in place when approached. That whole “don’t move and maybe they won’t see me” thing makes them easier to step on than spot.
They are small but pack venom that causes muscle breakdown and internal bleeding. Most bites happen to climbers or hikers in remote areas, which makes them extra dangerous because help is usually far away. If you are scrambling across boulders in the Davis Mountains or the Gila Wilderness, this is the guy hiding in the cracks just waiting to make your adventure unforgettable in the worst way.
16. Speckled Rattlesnakes stay hidden until your ankle is already in their strike zone.
You are probably not going to see this one coming. Speckled rattlesnakes are basically desert camouflage experts. They live in parts of the southwestern U.S., especially around southern California, southern Nevada, and western Arizona. Their coloring blends almost perfectly with rocky desert terrain, so by the time you realize what you are looking at, you are probably already too close.
These snakes prefer cliffs, canyons, and rocky outcrops. They are not aggressive, but they do bite when startled. Their venom is potent enough to cause necrosis and severe pain, but most people just do not even know to look for them. Hikers and climbers are the most frequent victims. The bites happen fast, often without warning, and in places where cell service is nonexistent. It is not a good time.
17. Twin-Spotted Rattlesnakes are tiny but live where the air gets thin and mistakes get costly.
These high-elevation rattlers are found in southeastern Arizona and nowhere else in the U.S., which makes them rare, but not rare enough if you like backpacking through sky island ranges like the Chiricahuas. They are small—usually under two feet—but do not let that fool you. Their venom is strong, and their environment makes things worse.
Most bites happen to hardcore hikers who are navigating steep trails or flipping over rocks without thinking. Because these snakes are only active during warm summer months and mostly stay hidden, people tend to underestimate the risk. But up in those mountains, even a small bite can spiral into a big problem fast, especially when it takes hours to get help.
18. Great Basin Rattlesnakes roam through six states and do not stick to one vibe.
Found from California to Idaho, the Great Basin rattlesnake is basically the generalist of the rattler crew. It does not have one set home style—it adapts to everything from desert valleys to grassy plateaus to rocky canyonlands. That flexibility means people across Nevada, Utah, and eastern Oregon run into them more than they realize.
Their venom is not as extreme as the Mojave’s or the eastern diamondback’s, but it still causes serious tissue damage and swelling. What makes them dangerous is their unpredictable territory. You could see one while fly fishing in a riverbed or hiking through sagebrush. They do not follow the typical snake rules, and that unpredictability is what keeps people ending up in the ER.
19. Northern Pacific Rattlesnakes are surprisingly common in spots you thought were safe.
A lot of people assume the Pacific Northwest is snake-free. It is not. Northern Pacific rattlesnakes show up in parts of northern California, Oregon, and even up into Washington state. They like dry forests, rocky hillsides, and sometimes even wine country trails where people are more focused on their Instagram story than their feet.
These snakes are chill most of the time. They rattle, they warn, they try to avoid conflict. But if you step near one or reach under a log without looking, the bite comes fast. Their venom isn’t the deadliest, but it is strong enough to cause hours of pain, swelling, and vomiting. They do not want the drama, but they will bring it if you catch them off guard.
20. Ridge-Nosed Rattlesnakes might be rare, but when they strike, it is serious.
Arizona’s state reptile is also one of the rarest venomous snakes in the U.S. The ridge-nosed rattlesnake lives mostly in the forested canyons of southeastern Arizona, especially the Huachuca and Santa Rita mountains. These snakes are tiny and shy, which is great until you realize they live in leaf litter and love staying hidden.
What makes them a problem is how silent they are. Their rattle is barely audible, and their coloring is a perfect match for the forest floor. Most people get bit while hiking or camping, especially if they sit or step in the wrong spot. Their venom causes intense localized pain and swelling, and while they are not high on the bite statistics list, the ER trips they do cause are rough. Think rare, but unforgettable in the worst kind of way.