Walnut Grove was a small town (now extinct) in Prairie Township, Warren County, Indiana, located three miles east of Tab. A 1913 history describes the town's population as about 50.
Walnut Grove is located in flat, open farmland at 40°24'40" North, 87°24'56" West (40.411210, -87.415640), at the intersection of County Roads 650 N and 500 W.