Final answer:
Oklahoma was the last U.S. state to make Christmas an official holiday in 1907, the same year it became a state.
Step-by-step explanation:
Oklahoma was the last U.S. state to declare Christmas an official holiday, doing so in 1907. This occurred at the time when Oklahoma was transitioning from a territory to a state.
The recognition of Christmas as an official holiday within the United States was not a simultaneous occurrence across all states. Each state, over time, decided on its own to formalize the celebration of Christmas as a state holiday. The last state to do so was Oklahoma. Officially becoming a state in November 1907, it was during that same year that Oklahoma enacted legislation to recognize Christmas as an official holiday.
Prior to this, while it was a territory, there was no official designation for the holiday. This move was part of a broader trend across the United States, during which the celebration of Christmas shifted from being seen as mostly a religious observance to a more secular and inclusive community event that involved a cessation of work and an opportunity for family gatherings. Today, Christmas is recognized as a federal holiday across all 50 states, ensuring that it is widely observed across the entire country.