How many Mormon churches in US?

Answer 1

There are approximately 13,470 congregations of the Church of Jesus Christ of Latter Day Saints (commonly called the "Mormon" Church) in the United States. In areas with a larger population of members (mostly in the western U.S.) it is common for two or three congregations to share one church building.

For more about Church population statistics try:

http://newsroom.lds.org/ldsnewsroom/eng/statistical-information
http://www.ldschurchtemples.com/statistics/

Or to find and visit the congregation nearest you, visit:

http://maps.lds.org

Answer 2

As of January 1, 2013 there were 13,742 congregations of the Church of Jesus Christ of Latter-day Saints (the "Mormon" church) in the United States.

This is not how many LDS church buildings or meetinghouses there are, however. It is very common for two, three, and sometimes even four congregations to share one church building. Additionally, some smaller congregations meet in homes or in rented buildings. The number of actual LDS church buildings/meetinghouses in the US is probably between 6,000 and 8,000.