1. On August 17, 1785, a state convention was held in Lancaster to ratify the United States Constitution. Pennsylvania became the second state to ratify the document, after Delaware.

2. In 1807, the Pennsylvania state legislature passed an act establishing a state penitentiary in Philadelphia. The Eastern State Penitentiary, which opened in 1829, was the first prison in the world to implement the principles of solitary confinement and rehabilitation.

3. On August 17, 1861, the 11th Pennsylvania Infantry Regiment was mustered into service for the Union army during the American Civil War. The regiment fought in numerous battles, including Antietam and Gettysburg, and was mustered out of service in 1864.

4. In 1915, the Keystone Automobile Club of Pennsylvania was founded in Pittsburgh. The club, which later became AAA East Central, provided roadside assistance and other services to motorists across the state.

5. On August 17, 1978, Camp Hill Prison, a maximum security facility near Harrisburg, was the site of a hostage crisis that lasted four days. Five prison staff members were taken hostage by inmates protesting prison conditions. The crisis ended peacefully with the release of the hostages.