Alum Creek rests in the midst of the fertile agricultural till plains and river valleys of Delaware County. In contrast to the surrounding farmlands, the park offers a diverse array of natural features. Cliffs of Ohio shale are notable in many areas, exposed as Alum Creek and other streams cut through underlying bedrock. The shale was formed as mud washed into the ancient sea which covered the area several hundred million years ago. The dark hue of the rock is due to the mixture of a carbonized plant material and mud that formed the shale.
The rich soils of Delaware County gave rise to a luxuriant beech-maple forest after the retreat of the glaciers about 12,000 years ago. That original forest has long since been cut but a healthy second growth forest is preserved in the park. The woodlands harbor a variety of plant species offering beautiful displays of wildflowers and wildlife. Large-flowered trillium, wild geranium, bloodroot, and spring beauties carpet the forest floor. The forest is home to the fox squirrel, woodchuck, rabbit, white-tailed deer and many other species of wildlife.
Alum Creek Reservoir contains 3,387 acres of water with surrounding field and woodlands encompassing 5,213 acres. Visitors will find a variety of activities available all season.