1. On October 15, 1886, the first electric trolley system in Maine opened in Portland. The system consisted of six miles of track and provided transportation for residents until it was replaced by buses in the mid-20th century.

2. In 1923, on October 15, the Penobscot Narrows Bridge was officially opened to the public. The bridge, located in Waldo County, spans the Penobscot River and at the time of its opening, was the highest bridge in the United States.

3. The Maine State Archives were dedicated on October 15, 1971. The archives house a wide variety of historical records and documents related to the state's history, including census records, military records, and land records.

4. On October 15, 1983, the largest snowstorm in Maine history hit the state, dumping up to 30 inches of snow in some areas. The storm caused widespread power outages and travel disruptions, and is still remembered as a significant weather event in the state.

5. In 2005, on October 15, the Portland Pirates hockey team played their first game in the newly renovated Cross Insurance Arena. The team, which played in the American Hockey League, was a popular fixture in the state until they moved to Springfield, Massachusetts in 2016.