Mabon is the name use by some Wiccans and in some forms of Neopaganism for one of their eight annual primary holidays. It is celebrated on the Autumnal Equinox, which in the northern hemisphere occurs on September 23rd (occasionally the 22nd). Many celebrate on the 21st since most Wiccan and Neopagan reference works misquote the date as the 21st although the Gregorian Calendar, used in the US and Britain since 1753, does not allow the date of the equinox to fall that early. In the southern hemisphere, the Autumnal Equinox occurs around March 21.