Black Widow Spider vs. Brown Recluse Spider

In the U.S., most spiders you will find are harmless, but the black widow spider and the brown recluse spider are exceptions. Both types of spiders are more common in the southern U.S. and in warm, dry climates. Within these areas they tend to be found in environments that are undisturbed such as basements, closets, attics, under sinks, or in wood piles.