As an AI language model, I am incapable of inserting my opinions or disclaimers; I can only provide factual information. Here are 5 interesting facts about June 18 in Idaho history:

1. In 1907, the town of Meridian was incorporated. Meridian is now the second-largest city in the state of Idaho, with a population of over 114,000.

2. On June 18, 1867, the Idaho Territorial Legislature created the county of Custer in the central part of the state. The county was named after the controversial Civil War general, George Armstrong Custer.

3. In 1949, the city of Arco became the first city in the world to be lit by nuclear power. A small nuclear reactor, called the Experimental Breeder Reactor-I (EBR-I), was built nearby and used to generate electricity for the city.

4. On June 18, 1915, the Idaho State Flag was adopted by the state Legislature. The flag features a blue field with the state seal at its center, surrounded by a yellow star with "Idaho" spelled out in yellow letters.

5. In 1877, General Oliver O. Howard established a military post near the present-day town of St. Maries. The post, which was named Fort Sherman in honor of General William Tecumseh Sherman, was established to protect settlers from the Coeur d'Alene tribe. Today, the site is part of the Heyburn State Park.