1. On May 31, 1919, Maine ratified the 19th Amendment, giving women the right to vote. This made Maine the 19th state to ratify the amendment, which eventually became part of the United States Constitution on August 26, 1920.

2. On May 31, 1855, the Maine State Reform School (now known as the Maine Youth Center) was established in South Portland. The school was initially created to provide education and training to troubled and delinquent boys, but it has since expanded its services to include girls.

3. May 31, 1944, marked the end of the historic "quarantine" of lobster fishing in Maine. Due to concerns about overfishing and declining lobster populations, the state had imposed a five-month ban on lobster fishing, which was met with protests and legal challenges from Maine's lobster industry.

4. On May 31, 1929, Maine's first public airport was dedicated in Portland. The airport, which was initially called the Portland Municipal Airport, was later renamed the Portland International Jetport and has since become one of the busiest airports in the state.

5. May 31, 1797, saw the birth of Winslow Homer, one of the most renowned American painters of the 19th century. Homer was born in Boston but spent much of his life in Maine, where he created many of his most famous works, including his iconic paintings of the rugged Maine coast.