Final answer:
Oklahoma was the last U.S. state to officially declare Christmas as a state holiday, doing so in 1907.
Step-by-step explanation:
The last U.S. state to make Christmas an official holiday was Oklahoma. The transformative moment occurred when the holiday found its way into the hearts of the American people and eventually into national observance. It wasn't until 1907 that Oklahoma officially declared Christmas as a state holiday, making it the last state in the United States to do so. This final acknowledgment by Oklahoma marked the full acceptance of Christmas as a key cultural and public event across the entire country.