Is owning a katana illegal in the US?

Excuse me, could you clarify for me if owning a katana, the traditional Japanese sword, is considered illegal in the United States? I've heard conflicting opinions and would like to ensure I have the correct information. Are there any specific laws or regulations that govern the ownership of katanas within the country? Additionally, are there any restrictions on how they can be transported or displayed? Thank you for your time and assistance in answering my question.