The 3 Biggest Spiders in Colorado

Written by Megan Martin
Published: August 18, 2022
© texas brown tarantula/
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There are at least 28 different species of spiders in Rocky Mountain state – including these 3 biggest spiders in Colorado. Spiders can come in a variety of shapes and sizes. Some are small enough that you can barely see them. Others, like those on this list, are sometimes larger than birds!

Although spiders, especially larger ones, can be intimidating, they’re usually more afraid of us than we are of them. Plus, the majority of spiders in the United States are harmless to humans. Even those that can bite us often don’t have side effects other than mild pain or swelling. In fact, out of thousands of species across the country, there are only around a dozen of medically significant species in the United States, none of which are on this list.

Are you ready to meet the three biggest spiders in Colorado? Let’s dive in!

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pet Tarantula
Tarantulas are more common in the southern parts of Colorado.


There are three different species of tarantula found in Colorado: the brown tarantula (Aphonopelma coloradanum), the Colorado chocolate brown tarantula (Aphonopelma echinum), and the Oklahoma brown (Aphonopelma hentzi). Although these species have a slight variation in size between themselves, they’re all top contenders for being some of the biggest spiders in Colorado.

The Oklahoma brown tarantula is the best documented of the three species. Also known as the Texas brown tarantula or the Missouri tarantula, this is one of the most common species of tarantula found in the southern region of the United States. They can grow to weigh as much as 3 ounces, larger than some species of hawks! As for their legs, they can grow to be as long as four inches. That’s the same as a credit card.

Although their place as one of the biggest spiders in Colorado can make them intimidating, the tarantulas of Colorado are virtually harmless. They’re docile and unlikely to respond with aggression. On the chance that you are bitten by a tarantula in Colorado, it’s unlikely to be medically significant unless you experience an allergic reaction or suffer an infection at the bite site.

Wolf Spider

Wolf Spider (Hogna baltimoriana)
Wolf spiders are some of the biggest spiders in Colorado.

©Aaron Carlson / flickr – License

There are nearly 3,000 species of wolf spiders found across the world, and they’re a common sight in Colorado. Unlike other types of spiders, the wolf spider doesn’t spin webs. Instead, these top predators will actually chase down their prey, just like their canine namesake!

The most common species of wolf spider in Colorado is the Carolina wolf spider (Hogna carolinensis). It also happens to be the biggest species of wolf spider in all of North America. Females, which are larger than males, can grow to be around 1.3 inches. That’s just a little bit bigger than your thumb. Some are large enough that they can be mistaken for tarantulas.

Although the wolf spider packs a powerful bite with paralyzing venom, it isn’t a huge threat to humans. A bite from one of these large spiders may lead to some localized numbness and a risk for infection. However, other than this, complications are rare.

Despite their place as one of the biggest spiders in Colorado, the wolf spider has a variety of predators. These can range from scorpions to coyotes!

Banded Garden Spider

Banded Garden Spider -Argiope trifasciata
Between their large size, bright colors, and webs, it can be hard to miss the banded garden spider.

©Ernie Cooper/

The banded garden spider (Argiope trifasciata) is just a few millimeters smaller than the wolf spider. At just under an inch long, it is the smallest spider on this list so far but still one of the biggest spiders in Colorado.

Also known as the banded orb-weaving spider, you’ve most likely seen a banded garden spider around. These are the bright yellow and black spiders that like to weave intricate webs in your garden and around the outside of your home. Due to the way they sit, with their legs together in pairs, they often appear to have four legs rather than eight.

Their role as one of the biggest spiders in Colorado isn’t the most interesting thing about them, however. Instead, it’s their web. One of the reasons that the garden spider is so notable is because of its highly visible webs. Scientists still aren’t entirely sure why these spiders build such large, noticeable webs. In fact, it’s even been shown that they may catch fewer insects in their webs compared to other spiders. However, at the same time, their webs are less likely to be destroyed by passing animals, such as by birds flying through them.

There are several types of orb weaver spiders in Colorado, but the banded is by far the largest.

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Texas Brown Tarantula standing in front of grass
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About the Author

I'm a writer with almost five years of experience. I recently graduated from Wingate University with a Bachelor of Arts in English and a double minor in biology and professional and technical writing. I love everything animals and nature related! The American kestrel is my favorite animal, but I also like sharks and alligators. In my free time, I like to watch documentaries and explore nature.

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