Based on my observations as an American citizen I would say Christianity. After all, there is a whole section of the United States called "The Bible Belt". This area got its name for the large Christian population there.
The most popular sport in America would have to be baseball.
Golden Retrievers are he third most Popular in America.
Catholicism
Garcia. It is the 8th most popular last name in America, making it the 1st most popular HISPANIC last name in America.
Karen Carpenter is the most popular Dangdut Songstress in America.
I think the robber fly is the most popular insect in America. It is just my opinion.
football (soccer) is the most popular sport in south America
Amish is most popular in Lancaster/York, America
The most popular girl name in 2008 (in North America) was Emma. The most popular boy name in 2008 (North America) was Aiden.
beef and chicken are the most consumed meats in america(1st and second most respectively).
Christianity, or in particular, Roman Catholics
Connor and Myles Faith and Hope