In fact in the latter 1800s, it was known exclusively in America as “a Scottish Halloween”, and was originally only engaged in by Rednecks (Scotch-Irish settlers), but it became something of a fad — that endured — among their better-healed Waspish neighbors in small town America of the Great Lakes, Upstate New York, and New England, becoming increasingly popular after 1880. The Scottish Hallow’een originated in Calvinist Scotland sometime in the 1600s. It consisted of a party with (1) various party-games, particularly bobbing (or dookin’) for apples and — blind-folded with hands tied behind your back — trying to eat treacle scones hanging on strings , (2) a bonfire, (3) carved turnips (neeps) with candles inside, and (4) telling ghost stories. There was also the Trick-or-Treat-like practice of “Guising” — which was a carryover over Medieval Wassailing, but for kids: children would put on flamboyant party clothes — not scary costumes — and go door-to-door to local parties and perform songs and dances, recite poems, and otherwise entertain in return for goodies. Guising, however, was never practiced by the American Scots, so any resemblance to Trick-or-Treating is purely coincidental.
Mischief Night (though the name did not show up until the late 1700s, and was first applied to another similar tradition in other parts of England on May 1st) had a longer tradition, and had its origins in Wales, Cornwall, and the Isle of Man sometime after the 1400s. Originally, men and older boys would go out at night banging on doors and windows with gourds and turnips, and make spooky sounds. At the beginning, it seems to have been a kind of spoof of All Saints Day, the idea being that if the following day was for the goody-two-shoes, the night before was clearly for spooks and the devil in us all. In America, however, it quickly became a practice for tween and teen boys to go out and count coup and play commando. By 1910 it was becoming increasingly vandalistic prompting concerned citizens, ministers, and youth leaders to tame it by innovating Trick-or-Treat.
And for the record, there is absolutely not one shred of evidence of any “pagan” origins or some pre-Christian Celtic day of the dead. All of those things you’ve heard and read to the contrary are just regurgitated urban legend and the inventions of 19th and 20th century pagan reconstructionists and fabulists like Jakob Grimm. For example, the first mention of Samhain dates from the Christian Court of Tara in the 10th Century, and there it’s only a harvest feast followed by a torchlit procession to a bonfire. Moreover, at the time the Irish sill followed the Greek liturgy in which All Saints is observed in April, not on November
Hallowe’en was a Scottish peculiarity, which was exported to the USA with Scots immigrants. Up until about fifty years ago it was quite unknown outside Scotland and America. It has since been introduced artificially across the world, with the specific purpose of selling more candy to children. I blame the great Charles M.Schulz and his terrific invention, the Great Pumpkin; even though Schulz had intended him as a caricature of the shallower aspects of Christmas.