Mud Caves, Show cave system in Anza-Borrego Desert State Park, United States.

The Mud Caves are a group of at least 22 caves in the Carrizo Badlands of Anza-Borrego Desert State Park, along the Arroyo Tapiado in San Diego County. Water flowing through a thick silt deposit carved them, an example of pseudokarst; some reach 1,000 feet in length and 80 feet in height. Named passages include Big Mud Cave, the only one on most maps, Chasm Cave with its skylight, and Carey's Big Mud Cave, the largest in the arroyo.

The cave system developed over millions of years when this region was covered by an ancient lake that gradually dried up. The silt layers deposited on the lake bed were carved away by flowing water and wind erosion.

The caves lie along the Arroyo Tapiado in the Carrizo Badlands, and their names come from what visitors see inside: Chasm Cave has a skylight opening in its ceiling, Plunge Pool Cave ends in a round room, and Carey's Big Mud Cave is the largest in the arroyo. Big Mud Cave is the only one marked on most maps, while Hidden Cave is impossible to find without precise directions.

Exploring requires protective gear like helmets and lights since passages are low and narrow in places. Good gripping shoes are important because the muddy ground can be slippery.

Chasm Cave is the one most often cited for its skylight, an opening in the ceiling that lets daylight into the chamber. Big Mud Cave is the only cave marked on most maps, while Hidden Cave is described as impossible to find without precise directions.