1. On June 17, 1757, the Battle of Plassey took place in India, which was a decisive victory for the British East India Company over the Nawab of Bengal. Although this event did not directly involve Delaware, it had significant implications for the region's colonial trade and economic ties with Great Britain.

2. On June 17, 1776, the Continental Congress appointed George Read, Caesar Rodney, and Thomas McKean as delegates from Delaware to sign the Declaration of Independence. These three men played a vital role in securing Delaware's support for the American Revolution and establishing it as the first state to ratify the new United States Constitution.

3. On June 17, 1863, the Battle of Aldie took place in Virginia as part of the Gettysburg Campaign during the American Civil War. Two Delaware regiments, the 1st and 2nd Delaware Infantry, participated in the battle and suffered significant casualties. The event marked a turning point in the war and contributed to the Union victory at Gettysburg.

4. On June 17, 1957, the USS Delaware, a nuclear-powered submarine, was commissioned by the United States Navy. The submarine was the first of its kind and represented a major milestone in American military technology.

5. On June 17, 1994, the Delaware River and Bay Authority completed construction of the Delaware Memorial Bridge Twin Span. The new bridge, which spans the Delaware River between Delaware and New Jersey, increased capacity for vehicular traffic and improved transportation between the two states.