How long did the first celebrate last?

According to the historical record, the Pilgrims' first Thanksgiving celebrations lasted three days. Interestingly enough, that may be understood as how long the celebrations last nowadays. Indeed, people often try to take off the day before or the day after Thanksgiving.

The day after Thanksgiving is the biggest shopping day of the year. So people may be gone from work Wednesday through Friday. But those days are often spent in setting up and taking down Thanksgiving and setting up for Christmas. Rarely do Thanksgiving celebrations last for more than the actual day. This holds true even though Thanksgiving leftovers may fill the plates for a number of meals thereafter.
3 days long