The Napa River flood of 1986 is considered by many to be the worst flood experienced by Napa, California, during the 20th century. Twenty inches of rain fell in a 48-hour period; 7,000 people were evacuated, 250 homes were destroyed and another 2,500 damaged. Three people died, and estimated damages reached $100 million.^{[1][2][3][4][5]}

Following the flood, residents expressed a renewed urgency to mitigate flooding caused by winter storms, creating obstacles that slowed the flow of the river on its course to the San Francisco Bay. Since the flood, the Napa County Flood Control and Water Conservation District has worked to control the floods by way of the Napa River Flood Project.^[6] Another flood of lesser proportions occurred on December 31, 2005, after over a week of rain.^[7] Smaller floods occurred in 1995 and 1997.