Most spiders you’ll find inside a Minnesota home belong to a handful of species, and none of them are dangerous. The usual suspects are American house spiders, cellar spiders, barn funnel weavers, yellow sac spiders, and jumping spiders. Each one favors a different part of your house, builds a different kind of web (or no web at all), and is easy to tell apart once you know what to look for.
American House Spider
The American house spider is the one most Minnesotans picture when they think of an indoor spider. It’s grayish to brownish with chevron-like markings on its abdomen and a body length just over a quarter inch. These are the spiders responsible for the messy, tangled cobwebs you find in basement corners, crawl spaces, and behind furniture. They pick a secluded, undisturbed spot, spin a loose web, and wait. If the web doesn’t catch anything after a while, they abandon it and build a new one somewhere else, which is why cobwebs accumulate in quiet areas of the house.
American house spiders are completely harmless. They’re shy, reluctant to bite, and spend most of their time motionless in their webs. They’re actually doing you a small favor by catching flies, gnats, and other insects that wander into their webs.
Cellar Spiders
Cellar spiders are the long-legged, delicate-looking spiders you find in basements, cellars, and crawl spaces. Their bodies are only about a quarter to a third of an inch long, but their thin, spindly legs make them look much larger. They’re gray or light brown and build tangled, messy webs in dark corners, often near the floor or ceiling.
They’re most common in spring and summer but can show up year-round in heated basements. When disturbed, cellar spiders have a distinctive defense: they vibrate rapidly in their webs, blurring their outline to confuse predators. They’re sometimes confused with daddy longlegs (harvestmen), but cellar spiders are true spiders with two body segments and silk-producing spinnerets. They pose no risk to people.
Barn Funnel Weavers
Barn funnel weavers are a type of funnel-web spider commonly found indoors in Minnesota. You can identify them by the pair of dark stripes running behind the head. They build flat, sheet-like webs with a funnel-shaped retreat at one end, typically in corners, closets, window frames, and along baseboards. The spider sits at the narrow end of the funnel and rushes out when it detects vibrations from prey hitting the sheet.
These spiders look alarming to some people because of the “funnel-web” label, but they’re not related to the dangerous Australian funnel-web spiders. Minnesota’s barn funnel weavers are harmless and rarely bite.
Yellow Sac Spiders
Yellow sac spiders are the one common Minnesota house spider worth knowing about, because they’re the most likely to bite. Inside homes, they’re found high up on walls near ceilings, where they build small silken tubes or sacs as daytime retreats. On light-colored walls, these sacs are easy to miss because they blend right in.
Unlike web-building spiders, yellow sac spiders are active hunters. They leave their retreats at night to search for prey, and that’s when they run into people. Bites typically happen when a spider gets trapped between skin and bedding, clothing, or shoes. One species in particular will bite without much provocation if it finds itself crawling on exposed skin.
Most bites are relatively painless and don’t cause serious problems. In more reactive cases, you may feel a burning sensation lasting up to an hour, followed by redness, swelling, and sometimes blistering over the next several hours. A small number of people experience mild systemic symptoms like low-grade fever, muscle cramps, or nausea. These bites are occasionally misdiagnosed as brown recluse bites, but they’re far less severe and rarely leave lasting marks.
Jumping Spiders
Jumping spiders are the most charismatic spiders you’ll encounter indoors. They’re compact, fuzzy, and have a pair of large forward-facing eyes that give them surprisingly good vision. Unlike most spiders, they’re active during the day and tend to show up on windows, sunny walls, and ceilings where the light is good. They don’t build webs to catch prey. Instead, they stalk insects and pounce on them with short, precise jumps.
If you’ve ever noticed a small spider that seems to track your movements and turn to face you, it was almost certainly a jumping spider. They’re curious and alert but completely harmless. Many people find them endearing once they get past the initial surprise.
What About Brown Recluse and Black Widow Spiders?
This is the question most people really want answered. Brown recluse spiders do not have established populations in Minnesota. The species lives in the south-central United States, and while an individual brown recluse can occasionally hitch a ride into the state inside shipped boxes or furniture, finding one in your Minnesota home is extremely unlikely. If you think you’ve spotted one, the odds are very high that you’re looking at a barn funnel weaver or another brown spider with similar coloring.
Northern black widows do exist in parts of Minnesota, primarily in undisturbed outdoor habitats like rock piles and woodpiles, but they rarely turn up inside homes. The vast majority of spiders you encounter indoors in Minnesota are harmless species that want nothing to do with you.
Keeping Spiders Out of Your Home
Spiders follow their food. If you have flies, gnats, moths, or other small insects in your house, spiders will move in to eat them. The most effective long-term strategy is reducing the insect population that draws spiders inside in the first place. Switching outdoor lights to yellow or sodium vapor bulbs makes them less attractive to flying insects, which in turn means fewer spiders setting up shop near your doors and windows.
Seal cracks and crevices around your foundation, doors, and windows. Make sure door sweeps and window screens fit tightly. Inside, reduce clutter in basements, attics, and storage areas, since spiders thrive in undisturbed spaces with plenty of hiding spots. Keep humidity low in these areas when possible. Seal stored cardboard boxes with tape so spiders can’t crawl inside and set up camp.
For spiders already in your home, vacuuming is the simplest solution. Vacuum up webs, egg sacs, and the spiders themselves. Cardboard sticky traps placed along baseboards and under furniture work well for monitoring and catching wandering spiders like sac spiders and jumping spiders. Outside, clear wood piles, leaf litter, and debris away from your foundation, and keep shrubs trimmed back far enough to let sunlight and airflow reach the gap between plants and your house walls.
Residual pesticides sprayed indoors may kill some of the insects that spiders eat, but they generally don’t provide reliable long-term spider control. Physical exclusion and habitat reduction work better and last longer.