Out of curiosity, what and where are laws regarding protesting? What states protesters can be on public land, and what actions they are not allowed to do? Like blocking people from walking, etc.

A question brought up from many perspectives. I remember when reading a story on this forum regarding protesting. One of the anti-gun rallies and the pro gun people counter protested. Someone stated about carrying guns at/near the building and the legal perspective of it, but I don't remember exactly the thread.

What are the legalities of protesting, where protests may be held, and/or loudness of the crowd.