Mud Spring is a fourth-magnitude spring with an oval-shaped pool about 85 feet long and 65 feet wide. The spring flows from a vertical vent in the center of the pool, producing a prominent boil on the surface. The spring forms the head of Mud Creek, with the discharge flowing down a meandering run toward the southwest for about 1 mile to Little Lake George. The spring is situated along a hiking trail and is a popular picnic area in the state forest.