Reformation Day is a religious holiday celebrated on October 31 in remembrance of the Reformation, particularly by Lutheran and some Reformed church communities. It is a civic holiday in Slovenia (since the Reformation contributed to its cultural development profoundly, although Slovenes are mainly Roman Catholics) and in the German states of Brandenburg, Mecklenburg-Vorpommern, Saxony, Saxony-Anhalt, and Thuringia. It is also a national holiday in Chile since 2008.

In the United States churches often transfer the holiday, so that it falls on the Sunday (called Reformation Sunday) on or before October 31, with All Saints' Day moved to the Sunday on or after November 1.^{[citation needed]}

Halloween (a shortening of All Hallows’ Evening),^[5] also known as Hallowe'en or All Hallows' Eve,^[6] is a yearly holiday observed around the world on October 31, the night before All Saints' Day. Much like Day of the Dead celebrations, the Christian feast of All Hallows' Eve, according to some scholars, incorporates traditions from pagan harvest festivals and festivals honouring the dead, particularly the Celtic Samhain;^[6][7][8] other scholars maintain that the feast originated entirely independently of Samhain.^[9] Typical festive Halloween activities include trick-or-treating (also known as "guising"), attending costume parties, carving jack-o'-lanterns, lighting bonfires, apple bobbing, visiting haunted attractions, playing pranks, telling scary stories, watching horror films, as well as the religious observances of praying, fasting and attending vigils or church services.^[3][2][4][1]

The word Halloween is first attested in the 16th century and represents a Scottish variant of the fuller All-Hallows'-Even ("evening"), that is, the night before All Hallows' Day.^[10] Although the phrase All Hallows' is found in Old English (ealra hālgena mæssedæg, mass-day of all saints), All-Hallows-Even is itself not attested until 1556.^[10]

Nevada Day commemorates the admission of the state of Nevada into the union on October 31, 1864. The first known observance of Nevada Day (originally known as "Admission Day") was by the Pacific Coast Pioneer society during the 1870s. It was not until 1933 that the state legislature designated October 31 as Nevada Day and a state holiday.

On this holiday all state, county and city government offices are closed, along with most schools and libraries.^[1] Some private businesses, like banks, also close at their discretion. In Nevada's capital, Carson City, a parade is held through the heart of downtown, as well as a carnival and several other events.^[2]