Why is Thanksgiving celebrated on a Thursday in the United States?

Thanksgiving is celebrated on a Thursday in the United States primarily due to President Abraham Lincoln's proclamation in 1863. Lincoln established Thanksgiving as a national holiday to be observed on the last Thursday in November. This decision was aimed at uniting the country during the Civil War and recognized the importance of gratitude and reflection during a tumultuous time.

The historical context of honoring the Pilgrims and harvest festivals does contribute to the significance of Thanksgiving, as these elements are part of the story behind the holiday. However, the establishment of the specific day of observance as Thursday stemmed directly from Lincoln's efforts to create a national tradition.