Thanksgiving changed dates for a few years during the depression when President Roosevelt tried to boost retail sales by extending the Christmas shopping season.

Since Lincoln, Presidents had traditionally declared the last Thursday of November as a "Day of Thanksgiving". Though the actual legal date of the public holiday was left to each state, all followed this schedule. However, in 1939, the last Thursday of November was on the 30th, leaving only 25 days until Christmas. Roosevelt decided to break tradition and declare the second to last Thursday of November, the 23rd, the Day of Thanksgiving that year to add an extra week to the traditional shopping season.

He issued his declaration with the changed date in August, only three months before the holiday, and this caused a number of conflicts with events previously scheduled for what everyone had assumed would be Thanksgiving on the 30th. Notably, several college football games had been scheduled on the 30th and would have had very little attendance because fans would have been at work on this now non-holiday Thursday.

Republicans generally opposed the change while Democrats backed Roosevelt. Critics dubbed the changed holiday "Franksgiving". In the end, 23 states moved their legal public holidays to the 23rd, 22 states kept in on the 30th, and three states declared both Thursdays to be holidays, giving their residents two Thanksgivings. A similar split occurred in 1940 when Roosevelt again declared the second to last Thursday of November as Thanksgiving.

By 1941, research by economists had shown that the extra week had not significantly boosted retail sales, and Congress decided to end the confusion by fixing the fourth Thursday in November as the permanent date for Thanksgiving. Because of that change, the holiday now falls between November 22 and November 28, inclusive.