Decorah Ice Cave State Preserve has one of the largest glacières (ice caves) in the Midwestern United States. It consists of a 3-acre (1.2 ha) parcel of land at the edge of Barbara Barnhart VanPeenen Memorial Park in the northern portion of the city of Decorah, in Winnesheik County, Iowa.
Ice caves are one characteristic of karst topography, along with sinkholes and cave systems, all of which are present in the area, a portion of the Driftless Area of Iowa.
The cave was given to Decorah in 1954, and remains the property of the city. It was declared a state geological state preserve in 1973. It was placed on the National Register of Historical Places in 1978.