1. On June 10, 1754, the Treaty of Albany was signed, establishing an alliance between the Iroquois Confederacy and the colonies of New York, Massachusetts, and Pennsylvania. This treaty was significant in that it marked the first formal agreement between the British colonies and a Native American tribe.

2. On June 10, 1789, New Hampshire became the ninth state to ratify the United States Constitution, thereby making it official. The state played a pivotal role in the Constitution's adoption, with its delegates voting in favor of the document at the Constitutional Convention in Philadelphia.

3. On June 10, 1808, the Dartmouth College case was decided by the United States Supreme Court. The case centered around the question of whether the state of New Hampshire could alter the charter of Dartmouth College without the consent of the college's trustees. The Supreme Court ultimately ruled in favor of the college, upholding the principle of private property and limiting the power of state governments over private institutions.

4. On June 10, 1861, the first soldiers from New Hampshire left for the American Civil War. The state was a key contributor to the Union's war effort, with over 29,000 men serving in the conflict. New Hampshire also played a significant role in the Union victory at the Battle of Gettysburg in 1863.

5. On June 10, 1997, New Hampshire adopted the Old Man of the Mountain as its official state emblem. The iconic rock formation, located in the White Mountains, had been a symbol of the state for over 200 years before collapsing in 2003. Today, the Old Man of the Mountain remains a beloved symbol of New Hampshire's rugged natural beauty and independent spirit.