Lawrence Woods State Nature Preserve is the largest known mature forest in west-central Ohio. Located in Hardin County, this 1035-acre area was used for timber harvesting until it was officially protected by the Ohio Department of Natural Resources in 1997. It contains more than 100 native species of spring wildflowers, along with upland forest communities such as oak-hickory and swamp communities including beech-maple, beech-oak-red maple, and maple-ash-oak. State nature preserves are intended not as parks but as sanctuaries for threatened species and diverse landscapes, supporting low-impact activities such as hiking, birdwatching, photography, and nature study.