Hardin City Woodland is a 25-acre preserve containing an upland forest. Named for the nearby remains of Hardin City, an early settlement, it is located six miles north of Eldora in the Iowa River Greenbelt of Hardin County. The area was purchased by the Iowa Conservation Commission in 1959 and was dedicated as a biological state preserve in 1968.

Located near the eastern edge of the Des Moines Lobe landform region, the preserve contains a steep, north-facing slope along the narrow divide of a large me­ander of the Iowa River. The meander loop surrounds an alluvial bench formed by floodwaters associated with the melting of the Des Moines Lobe glacier 10,000 to 13,000 years ago.