1. On October 20, 1820, Maine officially became a state, becoming the 23rd state in the United States.

2. In 1927, the Penobscot Narrows Bridge opened on October 20, connecting Verona Island and Prospect in Maine. This bridge was the first to utilize a cable-stayed design in the United States.

3. On October 20, 1814, during the War of 1812, British troops landed in what is now Hampden, Maine and began burning and raiding nearby towns along the Penobscot River.

4. The first recorded snowfall in Maine occurred on October 20, 1899, when several inches of snow fell in Bangor and surrounding areas. This was an unusually early snowstorm for Maine.

5. On October 20, 2003, Maine's first same-sex marriage ceremony was performed in Portland, Maine. However, the state did not legalize same-sex marriage until 2012.