1. Idaho became a state: April 5, 1890 is a significant day in Idaho history as it marks the day when Idaho officially became a state of the United States of America. Idaho became the 43rd state of America after a long wait of nearly 30 years since the nation's formation.

2. The Big Burn Fire: On April 5, 1910, a massive forest fire broke out and engulfed a large portion of Idaho and Montana. Known as the "Big Burn Fire", it was one of the largest forest fires recorded in American history, covering over 3 million acres of land in just two days. The fire was caused by a combination of hot, dry weather and strong winds, and it destroyed many towns, homes, and businesses in its path.

3. First US Forest Service ranger: On April 5, 1905, the U.S. Forest Service hired its first ranger, Ed Pulaski, who would go on to become a legendary figure in the history of forest firefighting. He gained fame during the "Big Burn Fire" in 1910, during which he led a group of firefighters to safety in a mine, where they survived the flames by using his invention, the "Pulaski tool."

4. Potlatch Riot of 1892: On April 5, 1892, a riot broke out between striking union miners and company officials in the town of Potlatch, Idaho. The incident began when the officials of the Potlatch Lumber Company tried to bring in replacement workers to break the strike. The miners and their supporters, however, confronted the replacement workers and a violent altercation ensued. The riot was eventually suppressed by the Idaho National Guard, but it resulted in four deaths and many injuries.

5. First female mayors elected: On April 5, 1918, two women were elected as mayors in Idaho, making them the first female mayors in the United States. Susanna M. Salter was elected mayor of Argonia, Kansas, in 1887, but technically, it took place before Idaho's. In Idaho, Mary Wright Sewall was elected as the mayor of Moscow, while Margaret Anderson was elected as the mayor of Rexburg. Both women were prominent suffragettes and their election marked a significant milestone in the women's rights movement in America.