Every year, Halloween falls on October 31 because the ancient Gaelic festival of Samhain is considered to be the first known source of Halloween, which takes place on this day. It marked an important time of year when times changed, but, more importantly, observers believed that the boundary between this and the next world was much smaller at this time, enabling them to communicate with the dead. This belief was shared by other cultures; a similar view is expressed about the Jewish holiday Yom Kippur, which reappears in October and includes prayers for the dead. This is also where Halloween gets its “haunted” meanings.
Halloween has obviously always been a popular holiday in America today, but it actually didn’t cross the Atlantic. The Puritans did not agree with the pagan roots of this holiday, so they did not participate in it. But when Irish and Scottish immigrants first came to America in large numbers, the holiday returned to the zeitgeist. The first American colonial Halloween festivities featured large community groups to commemorate the upcoming harvest, to tell ghost stories, to sing and dance.