1. On September 9, 1776, the Continental Congress officially named the new nation as the United States of America. The Declaration of Independence was signed on July 4 of the same year, and this resolution cemented the name of the new nation.

2. The Battle of Brandywine, also known as the Battle of Chadds Ford, was fought on September 9, 1777, during the American Revolution. It was a significant victory for the British troops and allowed them to capture Philadelphia from the Continental Army.

3. On September 9, 1831, the Maryland Colonization Society was formed. The society aimed to send free African Americans to Liberia in West Africa, where they could establish their own nation. The society's work continued until 1867.

4. The Chesapeake and Ohio Canal officially opened on September 9, 1850. It was a vital transportation route for goods and people from Washington, D.C., to Cumberland, Maryland. The canal ran for 184.5 miles and was used until 1924.

5. On September 9, 1973, Lieutenant Governor Blair Lee III became Governor of Maryland after Governor Marvin Mandel was convicted of racketeering and mail fraud charges. Lee served as governor until January 15, 1979, making him the longest-serving governor in Maryland's history.