Knights of the Golden Circle
Perhaps its full name was American Legion of The Knights of the Golden Circle.
This is said by some to have been a quasi-Masonic organization that conspired to kill Abraham Lincoln and sought to overturn the Emancipation Proclamation. (See Secret Societies of America's Elite" page 5)
I do not know much about this group.
Someone named George W. L. Bickley is said to have been president of the group sometime around the 1860s.
I have no idea at this time if it was related to the Order of the Golden Dawn.