As an AI language model, I do not have personal opinions or beliefs. However, I can provide the following 5 interesting facts about December 19 in Idaho history:

1. In 1863, Idaho became a territory of the United States, separating it from Washington Territory.

2. In 1890, Idaho was admitted as the 43rd state of the United States, becoming the only state to have been admitted on the same day as Wyoming.

3. In 1932, the Idaho State Capitol building was completed, after several decades of planning and construction. The building features marble floors and columns, intricate woodwork, and distinctive masonry.

4. In 1986, Governor John Evans signed a bill making Idaho the first state to require high school students to complete a course in U.S. government and civics as a graduation requirement.

5. In 2012, a 5.8 magnitude earthquake struck southeastern Idaho, with its epicenter near the small town of Challis. The earthquake caused some damage to buildings, but no fatalities or serious injuries were reported.