High Quality Content by WIKIPEDIA articles! Walnut Grove is a city in Redwood County, Minnesota, United States. The population was 599 at the 2000 census.Walnut Grove is the home of the Laura Ingalls Wilder Museum, dedicated to the author of the Little House on the Prairie books. Charles Frederic 'Freddy' Ingalls, (November 1, 1876 - August 27, 1877 in South Troy, Minnesota), the little brother of Laura Ingalls Wilder, was born in Walnut Grove.