Baker Swamp is a large wetland that developed in the course of the preglacial Marietta River, the main tributary of the preglacial Teays River in southeastern Ohio. The site was formerly a shallow lake which became impounded by a downstream blockage of the Teays River during a glacial advance. The sediments deposited on the lake bed form the area’s poorly-drained soils of today. These impermeable soils and the activity of beaver in the area have contributed to the formation of Baker Swamp.
Baker Swamp lies in the Western Allegheny Plateau Ecoregion and today consists of approximately 180 acres of shallow open-water wetland and cattail marsh. About 50 acres of buttonbush-alder shrub swamp occupy the southern portion of this preserve. Swamp forests occur to the east and north of the open-water zone. Timber cutting has reduced the dominance of pin oak, and the fast-growing red maple is the dominant species of this pin oak-red maple swamp forest today.