I wondered because, If you belong to a clan, you would know. If you surname was associated to a clan you might not know. There is a big difference. Many of the Clan associations in the US are like historical societies like the DAR and require documented family history to join. Just because a surname has it origin in Scotland or Ireland doesn't mean that you are an automatic member. If you name origin is from Scotland or Ireland, you could contact the society for that name and ask about the requirements of membership. It took me several years of do the research requires to join the Stewart Clan. I had only been doing genealogical researcher about 15 years then, now after over 35 years I have learned easier ways to locate documents that I needed to become a member.