Cold Water Spring State Preserve

Cold Water Spring State Preserve is a 60-acre protected area in northeastern Iowa centered on the spring flowing from Cold Water Cave into a tributary of the Upper Iowa River. Set within the Driftless Area, it is part of a karst landscape shaped by underground water, with sinkholes, disappearing streams, blind valleys, caves, cold springs, and cold streams. Its importance rests largely on Cold Water Cave, which stretches nearly 16 miles through Iowa into Minnesota and carries a substantial underground creek. The cave is notable for rapid expansion, low-oxygen and high-carbon-dioxide air, and its 1987 designation as a National Natural Landmark.

Cresco, Iowa · United States