Walnut Grove, Warren County, IndianaWalnut Grove was a small town in Prairie Township, Warren County, Indiana, located three miles east of Tab. A 1913 history describes the town's population as about 50.HistoryA post office was once established at Walnut Grove in 1872, and remained in operation until it was discontinued in 1900.GeographyWalnut Grove is located in flat, open farmland at the intersection of County Roads 650 North and 500 West.