List of rivers of Orange County, California

With the exception of mountain regions, Orange County is characterized by dense suburban and urban development.

To protect the county's 3 million people from floods, many streams were channelized and/or lined with concrete in the 20th century.

In addition, some wholly artificial streams were constructed to drain the large coastal wetlands and floodplains in north Orange County, namely in the Anaheim Bay watershed.

Such projects range from Irvine Lake – the county's largest body of fresh water, created by damming Santiago Creek in 1931 – to the extensive Santa Ana River groundwater recharge operations that provide as much as half the domestic water used in the county.

A number of smaller streams flow into the Pacific Ocean along the Orange County coast.