In the British Isles, most of continental Europe (including the masonically expanding states of eastern Europe), and most nations of the Commonwealth (with the notable exception of Canada), the teachings of Royal Arch Masonry are contained in the “Supreme Order of the Holy Royal Arch” – a stand-alone degree of Freemasonry which is open to those who have completed the three Craft degrees. Until 1823, only freemasons who had previously passed through the chair of a Craft lodge were allowed to join. Today, candidates for an English Holy Royal Arch Chapter are required to have been a Master Mason for four weeks or more.
In Freemasonry in Scotland, the candidate for the Royal Arch must also be a Mark Master Mason, a degree which can be conferred within a Royal Arch Chapter if required. In Ireland a candidate must be a Master Mason for one year before being admitted as a member of a Royal Arch Chapter. The Degree of Mark Master Mason is taken separately first and only then can the Royal Arch Degree be taken.
In the United States, Canada, Brazil, Israel, Mexico, Paraguay and the Philippines, the Royal Arch is not worked as a stand-alone degree as described above, but forms part of the York Rite system of additional Masonic degrees. Royal Arch Masons in the York Rite also meet as a Chapter, but the Royal Arch Chapter of the York Rite confers four different degrees: ‘Mark Master Mason’, ‘Virtual Past Master’, ‘Most Excellent Master’, and ‘Royal Arch Mason’. While the York Rite degree of ‘Royal Arch Mason’ is roughly comparable to the Supreme Order of the Holy Royal Arch as practised in England and Wales, the other degrees may have equivalents in other appendant orders.
The Royal Arch is also the subject of the 13th and 14th degrees of the Scottish Rite of Freemasonry (called “Ancient and Accepted Rite” in England and Wales).
(the source/read more: Wikipedia)