Is owning emulators illegal?

Could you please clarify for me if owning emulators is indeed considered illegal? I understand that emulators can be used to replicate the functionality of various hardware and software systems, but I'm unsure if simply possessing them falls under any legal restrictions. Is there a specific law or regulation that prohibits individuals from owning emulators, or does the legality depend on the intended use and the content being emulated? I would greatly appreciate your insight on this matter.