High Quality Content by WIKIPEDIA articles! Walnut Township is a township in Jewell County, Kansas, USA. As of the 2000 census, its population was 80.Walnut Township covers an area of 39.46 square miles (102.21 square kilometers); of this, 0.03 square miles (0.07 square kilometers) or 0.07 percent is water.Jewell County (county code JW) is a county located in North Central Kansas, in the Central United States. The population was estimated to be 3,324 in the year 2006.[1] Its county seat and most populous city is Mankato.