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What is the Biggest Spider in Oregon?

Oregon, with its diverse landscapes ranging from forests to beaches and urban areas, is home to a wide variety of wildlife, including a plethora of spider species. While spiders might send shivers down the spine of some, they are fascinating creatures that play a crucial role in our ecosystem. Today, we’re uncovering the mysteries of the biggest spider you can encounter in the Beaver State—the Giant House Spider (Eratigena atrica).

the biggest spider, the giant house spider, big brown and about 6 inches wide

The Giant Among Us: The Giant House Spider

The Giant House Spider holds the title for the largest spider in Oregon. These arachnids can have a leg span of far more than 4 inches, making them a significant presence in any room they inhabit. But fear not—despite their daunting size, these spiders are generally harmless to humans and prefer to keep to themselves.

Appearance, Habitat, and Behavior

Identifying the Giant House Spider is relatively straightforward, thanks to its size and webbing patterns. Their webs are usually funnel-shaped retreats where the spider hides, waiting for prey to stumble upon their silk trap. The Giant House Spider has a brown body with a darker center pattern on its abdomen, and its legs are covered in fine hairs. Their body can grow up to 3 inches (7.6 cm) wide with a leg span reaching far beyond that.

  • Possesses eight eyes, arranged in a tight cluster on the upper front part of the head.
  • Features a less hairy, more robust and rounded abdomen, with colors ranging from brown to black.
  • These spiders excel in web-building and climbing, as opposed to running and jumping.
  • They craft expansive webs to ensnare prey, retreating to their webs to await the entrapment of insects.
  • They have a preference for dark, moist environments such as home interiors, basements, garages, and sheds.

Giant house spiders are found in dark, damp places throughout the Pacific Northwest, including Oregon. While they may look scary, their venom is weak and not harmful to humans. You’re likely to find them in the corners of rooms, window frames, garages, or basements—anywhere they can find a quiet, undisturbed place to spin their webs and catch their next meal.

These spiders are known for their astonishing speed, especially when startled. They predominantly feed on insects, playing a beneficial role in controlling pest populations indoors and in gardens.

Other Big Spiders: Possible Lookalikes

Each of these spiders has unique characteristics that set them apart.  These lookalikes can often be mistaken for big spiders. However, it is important to learn the differences between these spiders in order to properly identify and address any potential pest problems.

another big spider found in Oregon the hobo spider, brown spider on a web

The Hobo Spider

  • Similar in size to Giant House Spiders, growing up to 2 inches (5 cm) wide with a leg span of 4 inches (10 cm).
  • Dark brown colored with a lighter brown hourglass marking on the underside of its abdomen.
  • Hobo spiders prefer to avoid humans and their bites are considered to be medically insignificant.
black widow spider making web on leaves

Western Black Widow

  • Smaller than Giant House Spiders and Hobo Spiders, with a body size of up to ½ inch (1.3 cm) and a leg span of 1 inch (2.5 cm).
  • Easily identified by their shiny black bodies with a red hourglass marking on the underside of their abdomen.
  • Black Widows are venomous, and while their bites are rarely fatal to humans, they can cause serious illness. 
a relatively big wolf spider on house plant

Wolf Spiders

  • Wolf spiders aren’t the largest in Oregon, usually reaching 1-1.5 inches (2.5-3.8 cm) in length. Still, some may find them “big.”
  • Wolf spiders are brown, gray, or black with hairy bodies and a long, narrow abdomen. Their color can lead to confusion with the Giant House Spider.
  • Hairy spiders, unlike most spiders like Giant House Spiders, don’t spin webs to catch prey. They’re active hunters that chase down their insect meals.
  • Wolf spiders have eight eyes in two rows, with larger eyes in front for better depth perception, aiding their hunting.
orb weaver garden spider

Orb Weaver / Garden Spiders

  • Not quite as big as Giant House Spiders, with a body size of up to ¾ inch (1.9 cm) and a leg span of 2 inches (5 cm).
  • Distinguished by their large, round webs and Spidersbodies that can be yellow, orange, or brown with black markings.
  • Orchard Orb-Weaver Spiders are not dangerous to humans and are beneficial predators of pest insects.
big yellow sac spider in oregon

Yellow Sac Spiders

  • Measuring up to 3/8 inch (about 1 cm) in length, are notably smaller and visually distinct from Giant House Spiders. They are pale yellowish or light green, a vivid contrast to the darker brown hue of Giant House Spiders.
  • Similar to the biggest spiders, Yellow Sac spiders do not build webs to catch prey. Instead, they hunt at night and hide during the day inside silk sacs they construct, which is where they get their name.
  • The Yellow Sac Spider has two rows of eyes of equal size, different from the Giant House Spider’s tight eye cluster.
  • Venom of the Yellow Sac Spider is considered more dangerous than that of Giant House Spiders, as their bites can cause mild pain and localized swelling.


The Ecological Role of the Giant House Spider

Despite the unease they might cause, spiders like the Giant House Spider play a vital role in our local ecosystems. By feeding on insects, they help control the populations of various pests that could otherwise damage crops, gardens, and invade our homes. Understanding this ecological contribution is essential to appreciating these eight-legged giants rather than fearing them.

Spider-proofing Your Oregon Home

For Oregon homeowners looking to coexist peacefully with these critters without sharing living spaces, here are some practical tips to spider-proof your home:

  1. Seal any cracks or openings around doors and windows.
  2. Keep outdoor lighting to a minimum, as it attracts the insects spiders feed on.
  3. Regularly clean and vacuum corners and hidden spaces where spiders might nest.
  4. Consider using natural deterrents like peppermint oil in areas where spiders are frequently seen.

By following these tips, you can reduce the chances of encountering these fascinating creatures indoors.

Prime Pest Solutions uses foundation treatment to prevent spiders in your home
the biggest spider in oregon on the wall, a giant house spider


Controlling the Biggest Spiders and Harmonizing with Our Oregon Ecosystem

Did you know? Spiders, especially the Giant House Spider, hold a special place in Oregon’s natural surroundings. Sure, they might look a bit intimidating, but let’s not forget the amazing benefits they bring to our ecosystem.

So, the next time you spot a spider hanging around your home, call Prime Pest Solutions! Share your spider tales or throw your questions our way. You never know, you might end up seeing these misunderstood critters in a whole new light.

At Prime Pest Solutions, we’re experts in handling even the biggest spiders in Oregon, including the Giant House Spider, while respecting the natural balance. Our pest control services in the greater Portland area are tailored to manage pests effectively and eco-consciously.

Need a spider-free home?

Contact us for a free estimate.

Our team is ready to ensure your space remains safe and enjoyable, with a deep understanding of Oregon’s ecosystem and its largest spiders.

More Spider Tips

What is the Biggest Spider in Oregon
How Do Spiders Make Webs?
Pictures of Different Types of Spiders