Muslims and mosques are much in the news with the current controversy over a proposed mosque near the World Trade Center site, as well as protests against mosques around the nation.

With all this attention on them, who are American Muslims?  Counting congregations and adherents can be difficult.  The US Census Bureau doesn't track religion data–in fact, unlike in other countries, it is barred from asking.  Social Explorer gives you access to the Association of Religion Data Archives (ARDA) data from 1980 to 2000.  Based on the Religious Congregations and Membership Study (RCMS), this is the most complete census available on religion in the United States.

According to the 2000 ARDA survey, New York City had 86 Muslim congregations and 167,259 adherents.  Nationwide, there were 1,209 congregations and 1,559,294 adherents.  You can explore where Muslims are in the New York City area and around the nation on this map.

Social Explorer's Andrew Beveridge wrote about the process of counting Muslims and other religious groups for GothamGazette.com.

Since Muslims, whatever their number, are a small part of the United States population they are hard to count. They are also hard to define. Considering just adults, what does one need to do to be counted as a Muslim? Go to a mosque? Pray several times per day? Observe Ramadan? Have made a pilgrimage to Mecca? Eat Halal foods? Those trying to count Jews face similar problems. One definition of Jewish, for instance, is "Feeling you should go to High Holiday services." By such a definition apparently, it is enough to either go to the services or to feel guilty about not going.

In this article, he also parses the different methods (and problems with them) used by researchers to count Muslims.  Click here to read the entire article.