This is that lousy town that Pa Ingalls occasionally hitched up the wagon to go drive to, right?
The area was long settled by various cultures of indigenous peoples. After European colonization began on the East Coast, pressure from settlement and other Native American tribes caused different peoples to migrate into the area. By the mid-nineteenth century Dakota language–speaking four divisions of the Dakota Sioux were the primary indigenous group in the territory.
Henry Jackson (1811–1857), one of the pioneers of Mankato, served as the first Justice of the Peace in St. Paul (1843), first Postmaster of St. Paul (1846–49), and a member of the first Territorial Assembly.[9]
Mankato Township was not settled by European Americans until Parsons King Johnson in February 1852, as part of the nineteenth century migration of people from the east across the Midwest. New residents organized the city of Mankato on May 11, 1858. The city was organized by Henry Jackson, Parsons King Johnson, Col. D.A. Robertson, Justus C. Ramsey, and unnamed others. A popular story says that the city was intended to have been named Mahkato, but a typographical error by a clerk established the name as Mankato.[10] According to Upham, quoting historian Thomas Hughes of Mankato, “The honor of christening the new city was accorded to Col. Robertson. He had taken the name from Nicollet’s book, in which the French explorer compared the ‘Mahkato” or Blue Earth River, with all its tributaries, to the water nymphs and their uncle in the German legend of Undine.’...No more appropriate name could be given the new city, than that of the noble river at whose mouth it is located.”[11] While it may or may not be true that the city was intended to be called Mahkato, the Dakota called the river Makato Osa Watapa (meaning “the river where blue earth is gathered.” The Anglo settlers adapted that as the Blue Earth River.[11] Notwithstanding the above history of the name for town of Mankato - Dakota word for Blue Earth, according to Frederick Webb Hodge, in his “Handbook of American Indians North of Mexico,” Volume 1, page 801, the town was named after the older of the two like-named chiefs of the Mdewakanton division of the Santee Dakota, whose village stood on or near the site of the present town.
Ishtakhaba, also known as Chief Sleepy Eye, of the Sisseton band of Dakota Indians was said to have directed settlers to this location. He said the site at the confluence of the Minnesota and Blue Earth Rivers was well suited for building and for river traffic, and yet safe from flooding.
Execution of the thirty-eight Sioux Indians at Mankato Minnesota, December 25, 1862
On December 26, 1862, the US Army carried out the largest mass execution in U.S. history at Mankato following the Dakota War of 1862. Thirty-eight Dakota Native Americans were hanged for their parts in the uprising. A military tribunal had sentenced 303 to death. President Lincoln reviewed the record and pardoned 265, believing they had been involved in legitimate defense against military forces. Episcopal Bishop Henry Benjamin Whipple had urged leniency in the case, but his position was not politically popular in Minnesota. Lincoln’s intervention was not popular at the time. Two commemorative statues are located on the site of the hangings (now home to the Blue Earth County Library and Reconciliation Park).
https://en.wikipedia.org/wiki/Mankato,_Minnesota
In the Little House on the Prairie television series, Mankato is a trading town that the citizens of Walnut Grove visit. It does not appear in the Laura Ingalls Wilder books.