1. Idaho Territory was established on August 16, 1863. President Abraham Lincoln signed the Idaho Territory Act into law, which created the territory out of land previously part of the Washington, Dakota, and Nebraska Territories.

2. Idaho's first telephone system was established in Helena, Montana, on August 16, 1881. The system connected Helena with Butte and Anaconda, Montana, and Idaho's capital city of Boise.

3. The state's largest recorded earthquake occurred on August 16, 1959. The magnitude 7.3 earthquake caused extensive damage in central Idaho, mainly in Challis and Mackay.

4. On August 16, 1976, the Teton Dam near Rexburg, Idaho, collapsed, causing a massive flood. The resulting flood water caused significant damage to the surrounding area, including the loss of 11 lives.

5. August 16, 2019, marked the 75th anniversary of the death of Ernest Hemingway. The famed author lived in Ketchum, Idaho, for many years and is buried in the town's cemetery.