The Delaware River has a long history of flooding. The river's floodplain, as well as those of its tributaries, has been subject to both local and widespread damage.

Yes, the Delaware River has a extensive and well-documented history of frequent and sometimes severe flooding. These are typically "fluvial" floods caused by intense precipitation from hurricanes, tropical storms, or "Nor'easters" that traverse the basin. Significant historic floods occurred in 1955 (Hurricane Diane) and June 2006, the latter of which set record crests in many areas. In 2026, flood risk management remains a top priority for the Delaware River Basin Commission (DRBC), as climate change has increased the frequency of localized, high-intensity rain events. Vulnerable communities like Trenton, NJ, and various towns in Warren and Hunterdon Counties are under constant monitoring. Modern 2026 flood insurance risk maps indicate that many properties along the main stem sit within the 100-year floodplain, meaning they have at least a 1% chance of flooding in any given year.