This 1,408-acre wildlife area lies in the grain farming country of west central Ohio, three miles south of Celina. It is bounded by U.S. Route 127 on the west and It’s It Township Road on the east; it extends approximately one-half mile south of State Route 703.
Mercer Wildlife Area is quite flat on the north side of the area bordering Grand Lake St. Marys. It is more rolling south of State Route 703. Approximately one-fourth of the wildlife area is in cropland and meadow. There are seven ponds (not shown on the map) totaling more than seven acres; the shallow bays of Grand Lake St. Marys make up the remainder of the area.