In the United States, the first recorded instance of a Halloween celebration occurred in Anoka, Minn., in 1921

Halloween did not become a holiday in America until the 19th century, where lingering Puritan tradition meant even Christmas was scarcely observed before the 1800s. North American almanacs of the late 18th and early 19th centuries make no mention of Halloween in their lists of holidays.

The transatlantic migration of nearly two million Irish following the Irish Potato Famine (1845–1849) brought the holiday and its customs to America. Scottish emigration from the British Isles, primarily to Canada before 1870 and to the United States thereafter, brought that country's own version of the holiday to North America.

When the holiday was observed in 19th-century America, it was generally in three ways. Scottish-American and Irish-American societies held dinners and balls that celebrated their heritages, with perhaps a recitation of Robert Burns' poem "Hallowe'en" or a telling of Irish legends, much as Columbus Day celebrations were more about Italian-American heritage than Columbus. Home parties would center around children's activities, such as bobbing for apples and various divination games, particularly about future romance. And finally, pranks and mischief were common on Halloween.

Commercial exploitation of Halloween in America did not begin until the 20th century. The earliest were perhaps Halloween postcards, which were most popular between 1905 and 1915, and featured hundreds of different designs. Dennison Manufacturing Company, which published its first Halloween catalog in 1909, and the Beistle Company were pioneers in commercially made Halloween decorations, particularly die-cut paper items. German manufacturers specialized in Halloween figurines that were exported to America in the period between the two world wars.

There is little primary documentation of masking or costuming on Halloween in America, or elsewhere, before 1900. Mass-produced Halloween costumes did not appear in stores until the 1950s, when trick-or-treating became a fixture of the holiday, although commercially made masks were available earlier.

In the United States, Halloween has become one of the most profitable holidays, next to Christmas, for retailers. In the 1990s many manufactures began producing a larger variety of Halloween yard decorations; prior to this a majority of decorations were homemade.

Some of the most popular yard decorations are jack-o'-lanterns, scarecrows, witches, orange and purple string lights, inflatable decorations such as spiders, pumpkins, mummies, vampires and Frankensteins, and animatronic window and door decorations.

Other popular decoration are foam tombstones and gargoyles.

Some cities like Anoka, Minnesota and The Village Halloween Parade draws tens of thousands of people.

In many towns and cities, trick-or-treaters are welcomed by lighted porch lights. In some large or crime-ridden cities, however, trick-or-treating is discouraged, forbidden, or restricted to staged trick-or-treating events within one or more of the cities' shopping malls, in order to prevent potential acts of violence against trick-or-treaters.

Those living in the country may hold Halloween parties. These parties usually involve games (often traditional games like bobbing for apples, searching for candy in a similar manner to Easter egg hunting, or a snipe hunt), a hayrack ride (often accompanied by a scary story and one or more masked and costumed people hiding in the dark to jump out and scare the riders), and treats (usually a bag of candy and/or homemade treats).

Scary movies may also be watched. Normally, the children are picked up by their parents at pre-determined times. However, it is not uncommon for these parties to include sleepovers.