Death cap mushrooms are common in certain parts of North America (such as the San Francisco Bay area) and are definitely known to grow in southern Oregon, New York and New Jersey. (You may be able to find them in other places, too.) It’s been noted that many victims of death cap poisoning are originally from Southeast Asia. Apparently, this is because the death cap mushroom is very similar in appearance to an edible mushroom called a paddy-straw that is common in those countries.
There are additional species of mushrooms that contain a high enough concentration of toxins to cause liver injury, such as the all-white destroying angels. These are close relatives to the death cap and are probably even more widespread.
It’s important to note that there are other mushrooms that can cause liver damage, and still others that are considered poisonous but may not necessarily cause liver damage. You can find additional information about this interesting field (known as mycology, the study of mushrooms) at wild mushrooms expert David Fischer’s site American Mushrooms.