Freedom of the press in the United States is protected by the First Amendment to the United States Constitution. This amendment is generally understood to prevent the government from interfering with the distribution of information and opinions. Nevertheless, freedom of the press is subject to certain restrictions, such as defamation law.

Answer this question: where did freedom of the press come from? Let's give stream of consciousness first:
The relevant information is: Freedom of the press in the United States is protected by the First Amendment to the United States Constitution.
So, the final answer is the First Amendment to the United States Constitution.