In the United States, by law, Thanksgiving Day cannot fall later than November 28. Each year, families nationwide celebrate Thanksgiving on the fourth Thursday of November. It is a harvest festival and, according to the U.S. government, an occasion for Americans to “express gratitude for the good things in life.”
The chosen date, established by Congress over eighty years ago, ensures Thanksgiving occurs between November 22 and November 28. This week-long range defines the possible dates for the fourth Thursday each year.
Thanksgiving traces back to a 1621 harvest feast shared by English colonists and Wampanoag Native Americans in what is now Massachusetts. However, the holiday did not always follow the current late-November schedule.
The National Archives notes that George Washington proclaimed Thursday, November 26, 1789, as a “Day of Publick Thanksgivin.” In the years afterward, Thanksgiving was celebrated on various dates, sometimes even in different months.
“Day of Publick Thanksgivin” — George Washington, November 26, 1789
In 1863, President Abraham Lincoln declared Thanksgiving to be observed on the final Thursday of November. Because November occasionally has five Thursdays, the holiday could fall on the month's last day.
This sometimes pushed Thanksgiving later in the month, but never beyond November 28 since the fourth Thursday cannot fall on the 29th or 30th.
Thus, the law and tradition strictly exclude November 29 and 30 as possible dates for Thanksgiving.
“A chance for Americans to express gratitude for the good things in life.” — U.S. Government
Author's summary: Thanksgiving in the U.S. is legally fixed on the fourth Thursday of November, which always falls between the 22nd and 28th, making November 29 and 30 impossible dates for celebration.