The 5 Largest Rattlesnakes in the United States

Written by Brandi Allred
Published: August 11, 2022
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Think You Know Snakes?

The largest rattlesnakes in the United States are some of the largest venomous snakes in North America. All rattlesnakes are pit vipers and share a few distinguishing characteristics. First, they come equipped with rattles that start out as tiny nubs on the tips of their tails. Rattlesnakes actually can’t rattle until they’ve grown up a little, at least enough to grow at least two rattle segments. They also have very large, hinged fangs at the front of their mouths. And, at the backs of their heads, they have huge venom glands to supply highly toxic venom to their needle-like fangs.

But, more than that, rattlesnakes can sense heat, so there’s no hiding from them. Though not aggressive, they’re known to bite in self-defense or when people accidentally step on them. That’s why it’s important to know about the largest rattlesnakes in the United States and how you can avoid them. Here, we’ll learn about some of the biggest rattlers out there and answer a few of your burning rattlesnake questions.

Keep reading to learn more about the largest rattlesnakes in the United States!

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5. Timber Rattlesnake

Timber rattlesnaake coiled in a loop
Found only in the eastern United States, these snakes are absent from the Florida panhandle and much of the Great Lakes region.

©Frode Jacobsen/

Timber rattlesnakes are some of the largest rattlesnakes in the United States. They grow up to five feet long, though most are around four feet long. They have light brown bodies with dark brown or black, hexagonal bands. Timber rattlesnakes spend their winters brumating and eating other snakes—including rattlesnakes and garter snakes—frogs, small mammals, and small birds.

4. Prairie Rattlesnake

These rattlesnakes occupy the Midwestern United States.


Also known as the Great Plains rattlesnake, these snakes are some of the largest rattlesnakes in the United States. They grow up to five feet long, though most are between 3-4 feet long. They lack the dark brown bands of timber rattlesnakes. Instead, prairie rattlesnakes are all over tan and light brown, with small blotches on their sides and large blotches on their backs.

3. Red Diamond Rattlesnake

Woman expertly removes huge snake
The red diamond rattlesnake has an extremely limited range.

©Creeping Things/

One of the largest rattlesnakes in the United States is the little-known red diamond rattlesnake. This snake grows up to 5.5 feet long, though most are under four feet long. It ranges from light brown to reddish-orange in color, with characteristic chainlike markings along its back. Like all pit vipers, red diamond rattlesnakes have vertically elliptical eyes similar to cat eyes.

2. Western Diamondback Rattlesnake

coiled western diamondback rattlesnake
Found throughout the western and midwestern United States, these snakes also live in Mexico.

©Audrey Snider-Bell/

Also known as the Texas diamondback rattlesnake, western diamondbacks are some of the largest rattlesnakes in the United States. They grow up to six feet long, with some reports of even larger specimens. Most adults top out around four feet long. These snakes have heavy bodies with tan, light, and medium brown scales that form diamond-like patterns along the back. Western diamondbacks have large, triangular heads and large eyes. They eat lizards, snakes, rats, birds, mice, and even insects.

1. Eastern Diamondback Rattlesnake

Large eastern diamondback rattlesnake
Like the red diamondback rattlesnake, the eastern diamondback rattlesnake has a very limited range.

©Chase D’animulls/

The eastern diamondback is the largest rattlesnake in the United States. These snakes grow up to eight feet long, though most reach only around six feet in length. They have distinct markings made up of light brown, tan, and dark brown scales arranged in chain-like patterns. Eastern diamondbacks live in the same areas as cottonmouths and copperheads, which leads many people to confuse the three venomous snakes. However, only eastern diamondbacks have rattles, and they’re the only one of the three with diamond-like markings.

Eastern diamondback rattlesnakes are primarily terrestrial, meaning they spend most of their time on the ground, not in the trees or in the water. They’re common in dry forests, swampy areas, prairies, and grassy marshes. When threatened, they coil into a defensive S position and rattle their large rattles in warning. However, rattlesnakes don’t always rattle in warning, and many bites have occurred with no warning rattle.

What is the Largest Rattlesnake?

The largest known species of rattlesnake is the eastern diamondback rattlesnake. These snakes grow up to eight feet long, though lengths of 4-6 feet are much more common. The largest eastern diamondbacks are always males, who grow slightly larger than females. They can weigh over ten pounds and have heavy bodies designed for life on the ground.

What State has the Biggest Rattlesnake?

Florida Rattler
The eastern diamondback is common in Alabama and other eastern states.

© Almeida

Since the largest rattlesnake in the world is the eastern diamondback, you could say that any state in which it lives has the biggest rattlesnake. The biggest rattlesnake lives in North Carolina, South Carolina, Florida, Georgia, Alabama, Mississippi, and Louisiana. 

How to Stay Safe Around Rattlesnakes

Rattlesnakes demand our attention and our respect. They’re dangerous creatures that should never be approached or harassed in any way. But, if you’re lucky enough to encounter one in the wild, here are a few tips for staying safe.

Staying safe around rattlesnakes starts with being aware of your surroundings. Never reach under bushes, rocks, or building debris that you can’t see into, as rattlesnakes often curl up in these areas. If you hear a rattle, walk away from it, not towards it. The same goes for seeing the snake itself; look, but don’t approach, and never attempt to touch. Remember, rattlesnakes are not aggressive, but they will act to defend themselves if you get too close. If you sustain a bite from a rattlesnake, seek immediate emergency medical attention, as bites can easily become life-threatening.

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Eastern Diamondback Rattlesnake Close Up

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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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