1. On March 9, 1641, the Maryland General Assembly passed an act that required all tobacco cultivated in the colony to be inspected and graded before it could be exported. This helped to ensure the quality of Maryland tobacco, which was highly prized in Europe.

2. March 9, 1776 marks the date when the Maryland Convention authorized the formation of six rifle companies to serve in the Continental Army during the American Revolution. These companies became part of the famous Maryland Line and played a key role in the Battle of Brooklyn in August of that year.

3. In 1862, on March 9, the USS Monitor, the first ironclad warship in the US Navy, sank off the coast of Cape Hatteras, North Carolina. The ship had gained fame for its duel with the Confederate vessel CSS Virginia just a year earlier, and its sinking was a major loss for the Union Navy.

4. On March 9, 1922, the Johns Hopkins University School of Medicine announced that it had successfully performed a liver transplant in a dog. This was the first time such a procedure had been attempted, and it paved the way for later efforts to perform liver transplants in humans.

5. March 9, 1964 was the date of the first official dedication of the Chesapeake Bay Bridge-Tunnel, which connects Virginia's Eastern Shore with Hampton Roads. The 17.6 mile-long structure is considered a marvel of engineering and has become an iconic landmark in the region.