<P> At the end of this book, the family is told that the land must be vacated by settlers as it is not legally open to settlement yet, and in 1870 Pa elects to leave the land and move before the Army forcibly requires him to abandon the land . </P> <P> Many of the incidents in the book are actual situations that happened to the Ingalls family at that time in their lives as told to Laura by her Pa, Ma and sister Mary over the years . Because Laura was, in fact, 2 to 31⁄2 years old while her family lived in Indian Territory during 1869--1870, and did not remember the incidents herself, Laura did more historical research on this novel than on any other novel she wrote, in an attempt to have all details as correct as possible . </P> <P> On the Banks of Plum Creek, published in 1937 and fourth in the series, follows the Ingalls family as they move from Pepin, Wisconsin to Kansas to an area near Walnut Grove, Minnesota, and settle in a dugout "on the banks of Plum Creek (Redwood County, Minnesota)". In reality, the occurrences and anecdotes in the first book Little House on the Prairie took place after their return from Indian Territory . The Ingalls family left for their journey to Minnesota on Laura's seventh birthday, February 7, 1874 . In this book, Laura is between the ages of seven to nine years old, which was chronologically correct . </P> <P> During the course of the story, Jack, the family bulldog, moves with the family to Plum Creek, though in real life he did not make the journey with the family . Readers liked Jack so much that Laura decided to include him in this book . </P>

Where is walnut grove in little house on the prairie