One of the primary problems with raising goats in the US is Selenium. Goats are very specific in how much they need as a minimum, but also have a maximum count. A goat will need at least 0.2 parts per million of selenium, but anything over 3 ppm is toxic to them. Much of both Dakotas, Idaho, Navada, Arizona, New Mexico, California, etc are simply too heavily concentrated for easy goat raising. In other places, huge patches where none can be found at all, requiring supplimental selenium.
With all that in mind, I thought this little chart might come in handy for those who would really like to raise goats and can accept some of the down-sides to them. I would still suggest doing soil tests of your specific land since the levels in any given area can vary greatly.