Mayfield Slough is a tidal slough located within the Palo Alto Baylands Nature Preserve in Santa Clara County, California. It is a coastal saltwater feature influenced by the tides of San Francisco Bay. A primary public access point for paddlers is the Palo Alto Boat Launch at the eastern end of Embarcadero Road, which provides direct entry to the slough. The waterway connects to the larger 618-acre Palo Alto Flood Control Basin, which collects flows from several creeks including Matadero Creek that feeds into Mayfield Slough. The slough is bordered by the Byxbee Recreation Area, and paddlers can explore the interface between the open water and the muted tidal marsh. The overall character is that of a flatwater, marshy bayland environment with views of the surrounding preserve and distant hills.

Paddling here is entirely dependent on the tide, and real-time water level data is available from the Mayfield Slough Tidal Station operated by NOAA. Paddlers must consult this data and plan their trips accordingly, as water levels can vary significantly. The area is known for abundant birdlife, including California Gulls, American White Pelicans, and burrowing owls in the adjacent Byxbee Park. Beavers have also been reported in the slough. The setting is largely natural and open, with wide skies and marsh grasses, though the ambient drone of nearby Highway 101 is often audible. The slough is part of a network of waterways including Charleston Slough and Adobe Creek, allowing for potential route exploration within the baylands complex.