Niland Geyser is a moving mud pot or mud spring outside Niland, California in the Salton Trough in an area of geological instability due to the San Andreas fault, formed due to carbon dioxide being released underground. It is the only mud pot or mud volcano known to have moved so significantly. The geyser has required costly engineering works since 2018 as it has impinged on the Union Pacific Railroad, California State Route 111, and other infrastructure.

A mudpot, or mud pool, is a type of acidic hot spring, or fumarole, with limited water. It usually takes the form of a pool of bubbling mud, as a result of the acid and microorganisms decomposing surrounding rock into clay and mud.