1. On March 20, 1638, Swedish colonists under the leadership of Peter Minuit landed in present-day Delaware and established the colony of New Sweden. This marked the first permanent European settlement in the area now known as Delaware.

2. On March 20, 1777, the Battle of Quinton's Bridge took place in Salem County, New Jersey, which at the time was considered part of Delaware. The battle was part of the American Revolutionary War and resulted in a British victory.

3. March 20, 1824, was the date of the incorporation of the Delaware Historical Society. The organization was founded to preserve and promote Delaware's history and cultural heritage.

4. On March 20, 1891, the first bridge spanning the Delaware River between Trenton, New Jersey, and Morrisville, Pennsylvania, was officially opened. The bridge, known as the Trenton-Morrisville Toll Bridge, allowed for increased transportation and commerce between the two states.

5. March 20, 1965, was the date of the groundbreaking ceremony for the Delaware Memorial Bridge Twin Span, which connected Delaware and New Jersey over the Delaware River. The bridge was completed in 1968 and continues to be a vital transportation link in the region.