All Hallow's Eve and Samhain have long been traditions celebrated in the Pagan communities. This is my favorite holiday and time of the year.
Several years ago,
History.com published a great article about Halloween, it's origins and the various traditions around the world. Here are some exerts from that article:

The American
tradition of "trick-or-treating" probably dates back to the
early All Souls' Day parades in England. During the festivities, poor
citizens would beg for food and families would give them pastries
called "soul cakes" in return for their promise to pray for
the family's dead relatives.
The distribution of soul cakes
was encouraged by the church as a way to replace the ancient practice
of leaving food and wine for roaming spirits. The practice, witch was
referred to as "going a-souling" was eventually taken up by
children who would visit the houses in their neighborhood and be
given ale, food, and money.
The tradition of dressing in
costume for Halloween has both European and Celtic roots. Hundreds of
years ago, winter was an uncertain and frightening time. Food
supplies often ran low and, for the many people afraid of the dark,
the short days of winter were full of constant worry. On Halloween,
when it was believed that ghosts came back to the earthly world,
people thought that they would encounter ghosts if they left their
homes. To avoid being recognized by these ghosts, people would wear
masks when they left their homes after dark so that the ghosts would
mistake them for fellow spirits. On Halloween, to keep ghosts away
from their houses, people would place bowls of food outside their
homes to appease the ghosts and prevent them from attempting to
enter.

The Celts, who
lived 2,000 years ago in the area that is now Ireland, the United
Kingdom, and northern France, celebrated their new year on November
1. This day marked the end of summer and the harvest and the
beginning of the dark, cold winter, a time of year that was often
associated with human death. Celts believed that on the night before
the new year, the boundary between the worlds of the living and the
dead became blurred. On the night of October 31, they celebrated
Samhain, when it was believed that the ghosts of the dead returned
to earth. In addition to causing trouble and damaging crops, Celts
thought that the presence of the otherworldly spirits made it easier
for the Druids, or Celtic priests, to make predictions about the
future. For a people entirely dependent on the volatile natural
world, these prophesies were an important source of comfort and
direction during the long, dark winter.
Over the years
traditions changed, and in America, people began to dress up in
costumes and go house to house asking for food or money, a practice
that eventually became today's "trick-or-treat" tradition.
In the late 1800s, there was a move in America to mold Halloween
into a holiday more about community and neighborly get-together's,
than about ghosts, pranks, and witchcraft. Because of their efforts,
Halloween lost most of its superstitious and religious overtones by
the beginning of the twentieth century.
Between 1920 and
1950, the centuries-old practice of trick-or-treating was revived.
Trick-or-treating was a relatively inexpensive way for an entire
community to share the Halloween celebration. In theory, families
could also prevent tricks being played on them by providing the
neighborhood children with small treats. A new American tradition
was born, and it has continued to grow. Today, Americans spend an
estimated $6.9 billion annually on Halloween, making it the
country's second largest commercial holiday.

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