This 9,230-acre wildlife area lies in the grain farming country of north-central Ohio, eight miles south of Upper Sandusky. Wyandot County Road 115 provides access from State Route 294, two miles west of Harpster, and from State Route 309, eight miles west of Marion. State Routes 67 and 294 border the area on the west and north. Killdeer Plains Wildlife Area is quite flat, with little natural drainage; however, land adjacent to the Little Sandusky River on the east edge of the area is quite rolling. Approximately two-thirds of the area is in cropland and grassland. The other one-third is divided almost equally between woods and shrubby coverts and water. The water areas include more than 1,000 acres of marsh, a 360-acre greentree reservoir, an upground reservoir, and 125 ponds ranging from less than an acre to 50 acres in size. Most small ponds are not shown on the map. Scattered remnants of the formerly extensive tall-grass prairie can still be found on the area. Fields that have been overgrown with dense brush are being replanted to native prairie species and managed with controlled burning. Prairie dock, grayheaded coneflower, saw-toothed sunflower, and dense blazing star add midsummer color to the remnant prairies. In the fall, big and little bluestem and Indiangrass dominate the landscape.