1. On February 23, 1864, the Battle of Island Number Ten occurred during the American Civil War. Confederate troops successfully defended the island on the Mississippi River, but ultimately the Union army's naval blockade caused them to surrender.

2. Clara Barton, founder of the American Red Cross, was born in Oxford, Maryland on February 23, 1821. She is renowned for her work as a nurse during the Civil War and her contributions to disaster relief efforts.

3. On February 23, 1960, the first successful flight of a rocket-assisted takeoff (RATO) was completed at the Naval Air Test Center in Patuxent River, Maryland. RATO was used to aid military aircraft in taking off from short runways or carriers.

4. In 1904, the first successful surgical separation of conjoined twins was performed in Baltimore, Maryland. The twins, named Violet and Daisy, were joined at the abdomen and lower spine. Dr. Henry J. T. Frank and his team successfully separated the twins, and they both lived long lives.

5. On February 23, 1969, the USS Maryland (SSBN-738), a United States Navy Ohio-class ballistic missile submarine, was commissioned. The USS Maryland was the fourth submarine of its class and served in various capacities during the Cold War and beyond.