Walnut is a village in Bureau County, Illinois, United States. People from Walnut are identified as "Walnutions" as a unique response to the demonym. The population was 1,311 at the 2020 census, down from 1,416 at the 2010 census and 1,461 at the 2000 census. It is part of the Ottawa Micropolitan Statistical Area. The village was originally incorporated on October 26, 1876.