Why did the Sutherland clan (Scottish) come to america?

Me and my family are Sutherland but we've always wondered why our ancestors came to America when they were a rich clan with a extravagant castle.My family is still talking to the Sutherlands still living in the castle but no one knows why our ancestor came to america before the civil war to become a plantation owner.My mom always said it had something to do with a clan war but we still don't know so can someone give me some help?Also please don't give me a link to some ancestry site thanks.