1. On June 4, 1855, the Maine State Agricultural Society held its first annual cattle show and fair in Portland. The event showcased various livestock breeds and agricultural products, and was attended by thousands of visitors. The society later evolved into the Maine Agricultural and Mechanical Association, which organized the widely popular Eastern States Exposition.

2. June 4, 1919 was the day when Maine became the first state to ratify the 19th Amendment to the US Constitution, granting women the right to vote. The amendment passed in the Senate in 1919, but it took until 1920 for the required number of states to ratify it, and for it to become a permanent law.

3. The deadliest fire in Maine's history occurred on June 4, 1947, when a blaze broke out in a midtown section of Bar Harbor. The fire quickly spread through the town, fueled by dry weather and high winds, and destroyed over 200 homes and businesses. Miraculously, only two people lost their lives, but the event marked a significant turning point in the town's history.

4. On June 4, 1963, President John F. Kennedy signed the Equal Pay Act into law, which aimed to eliminate wage disparities based on gender. The law required employers to pay male and female workers equally for equal work performed, but it did not fully achieve its intended goal, and pay equity remains an ongoing issue.

5. The 2018 Maine primary elections were held on June 4, marking a significant shift in the state's political landscape. Several key races, including the primaries for governor and both US House seats, saw a new generation of candidates challenge established political figures. The results reflected a growing trend of progressive activism and grassroots organizing in Maine politics.