These religious freedoms along with other freedoms were in the Bill of Rights, also known as the first ten amendments to the United States Constitution. The Bill of Rights was ratified in 1791 and brought along freedoms and protection for United States citizens.
The first amendment in the Bill of Rights talks about the freedom of religion and the freedom to practice any religion. Along with this, it talks about freedom of speech, freedom of assembly, and freedom of the press.
The religious freedoms that swept the United States following the Bill of Rights lead to a lot more people being open and peaceful with one another and accepting new religions and ideas. People from other countries would even come settle in the United States to practice their religion freely, which caused the U.S. to grow. This also caused religion to spread rapidly and more people started to do religious practices.