There’s not much information in the canon about witches and wizards in the United States. Rowling mentions a couple of American Quidditch teams in Quidditch Through the Ages, including one in my home state of Texas, as well as the American broom game called Quodpot, and we all remember the cryptic mention of the Salem Witches’ Institute in Goblet of Fire. However, buried in a news report from the currently-ongoing Quidditch World Cup in Patagonia was a very interesting little nugget of new information: the name of the governmental organization in the US which is the equivalent of the British Ministry of Magic! Not only that, but the name of the President is also included (and no, it’s not Barak Obama, although that does sound like a fantastic Wizarding name, if you ask me).
According to the Daily Prophet article, straight from the pen of J.K. Rowling under the pseudonym of Ginny Weasley, the governing body for magic in the USA is called the MACUSA (Magical Congress of the United States of America). The President of the Magical Congress is President Samuel G. Quahog.
So there you have it. One can’t help but wonder if the Magical Congress is as polarized and unable to get anything done as it’s Muggle counterpart.