The term American Buddhism can be used to describe all Buddhist groups within the United States, including Asian-American Buddhists born into the faith, who comprise the largest percentage of Buddhists in the country.
American Buddhists come from many national origins and ethnicities. In 2012, U-T San Diego estimated U.S. practitioners at 1.2 million people, of whom 40% are living in Southern California. In terms of percentage, Hawaii has the most Buddhists at 8% of the population, due to its large Asian-American community.
Hawaii has the largest Buddhist population by percentage, amounting to 8% of the state's population. California follows Hawaii with 2%. Alaska, Arizona, Colorado, Connecticut, Illinois, Kansas, Louisiana, Maine, Maryland, Massachusetts, Michigan, Missouri, Montana, New Mexico, New York, Ohio, South Dakota, Tennessee, Texas, Utah, Vermont, Virginia, Washington, Wyoming have a Buddhist population of 1%.
The following is the percentage of Buddhists in the U.S. territories as of 2010:
Buddhist American scholar Charles Prebish states there are three broad types of American Buddhism:
The oldest and largest of these is "immigrant" or "ethnic Buddhism", those Buddhist traditions that came to America with immigrants who were already practitioners and that largely remained with those immigrants and their descendants.
The next oldest and arguably the most visible group Prebish refers to as "import Buddhists", because they came to America largely in response to interested American converts who sought them out, either by going abroad or by supporting foreign teachers; this is sometimes also called "elite Buddhism" because its practitioners, especially early ones, tended to come from social elites.
A trend in Buddhism is "export" or "evangelical Buddhist" groups based in another country who actively recruit members in the US from various backgrounds. Modern Buddhism is not just an American phenomenon.