India, Nov. 26 -- Thanksgiving returns on November 27 this year, landing once again on the familiar fourth Thursday of the month. It's a date Americans see every year, yet the way it ended up locked into the calendar took a long, uneven path.

The earliest national link to the holiday goes back to 1789, when President George Washington declared November 26, a Thursday, as a "Day of Public Thanksgiving." He issued the proclamation after a request from the first Federal Congress. As noted by the National Archives, the country's new Constitution had only recently gone into effect, making the declaration a symbolic moment for the young nation.

The holiday didn't settle into an annual pattern until 1863, when President Abraham Lincoln designa...