1. On October 21, 1796, the town of Hallowell was officially incorporated, making it one of the oldest towns in Maine. Hallowell played an important role in Maine's shipbuilding and lumber industries during the 19th century.

2. On October 21, 1820, Maine officially became the 23rd state in the United States. This came after years of negotiations between Maine and Massachusetts, which had governed Maine as a district for over two decades.

3. October 21, 1854, marked the opening of the first railroad in Maine, the Atlantic and St. Lawrence Railroad. The line connected Portland to Montreal, Canada, and played a vital role in transporting goods and passengers throughout the state.

4. In 1911, the Great Fire of 1911 broke out in downtown Bangor on October 21, destroying over 250 buildings and leaving thousands homeless. The fire, which was caused by a faulty electrical wire, remains one of the most destructive fires in Maine's history.

5. On October 21, 1954, Hurricane Hazel made landfall in Maine, causing widespread damage and flooding along the coast. The storm, which had already devastated parts of the Caribbean and North Carolina, resulted in the deaths of four people in Maine and caused millions of dollars in damage.