1. On September 15, 1783, the "Peace of Paris" was signed, officially ending the American Revolutionary War. Connecticut played a crucial role in the war effort, supplying troops and resources to the cause.

2. In 1830, the first railroad in Connecticut opened, connecting New Haven to Hartford. This transportation milestone helped to spur industrial development throughout the state.

3. On September 15, 1877, the world's first working telephone exchange was established in New Haven. This innovation revolutionized communication both in Connecticut and around the world.

4. In 1935, the Mark Twain Memorial in Hartford was dedicated on September 15. The memorial serves as both a tribute to the iconic author and a cultural landmark for the state.

5. On September 15, 1978, the Connecticut Huskies football team played their first game as a Division I-A program, defeating Holy Cross 24-21 in front of a home crowd in Storrs. This marked a major step forward for the program and cemented UConn's place in the upper echelon of college football.