Treaty of Mendota, 1851

The Treaty of Mendota was signed by the Mdewakanton and Wahpekute bands of Dakota and the US government in 1851. By signing it and the Treaty of Traverse des Sioux the same year, the Dakota transferred ownership of much of their lands to the United States. The two treaties opened millions of acres to white colonization, but for the Dakota, they were a step towards the loss of their homeland and the US–Dakota War of 1862.

By 1849 there was great demand for the lands of the Dakota to be acquired by the United States. The white population of Minnesota Territory had not outgrown the lands acquired from the Dakota in the 1837 Treaty, but some colonists had begun squatting on unceded Dakota lands. A tide of western migration was close at hand, and the Dakota lands were attractive to land speculators. Territorial Governor Alexander Ramsey began to push for a new treaty in 1849. He was aided in his efforts by territorial delegate and trader Henry Sibley. The Dakota owed Sibley, and other traders, a great deal of money. Ramsey, and his fellow commissioner Luke Lea, represented the United States Government in the treaty process. Sibley rallied the numerous traders and attempted to exert his influence upon the Dakota.

First, the treaty delegation traveled to Traverse des Sioux and negotiated a treaty with the upper bands of the Dakota which included the Wahpeton and Sisseton. The Treaty of Traverse des Sioux was signed July 23, 1851. The vast majority of the chiefs also signed a trader's paper, which directed the government to first pay debts claimed by traders using the money promised to the upper bands. Afterward the treaty delegation traveled to Mendota to meet with the two lower bands of the Dakota, the Mdewakanton and Wahpekute.

The negotiations began on July 29, 1851 in one of Sibley's warehouses. They then moved to Pilot Knob where an arbor was erected. The Mdewakanton and Wahpekute were in a stronger position than the upper bands when it came to negotiations. They were not as desperate for food and goods. Further, the Mdewakanton had learned much from the Treaty of 1837. However, the treaty commissioners pointed out that with the sale of the upper bands' land, the Mdewakanton and Wahpekute would be surrounded by white colonists, and eventually forced to give up their land.

Led by Ta Oyate Duta (His Red Nation, also known as Little Crow IV) and Wabasha III, the Dakota asked that an annuity from the 1837 treaty be paid before there was any further discussion. The bands also tried to change the boundaries of the proposed reservation. These issues stalled the negotiations until August 5, 1851. It was agreed that $30,000 would be paid to the Dakota immediately in place of the 1837 annuity. The commissioners stated that the reservation borders were not negotiable. Many of the younger tribal leaders threatened their senior chiefs with death if they signed. Even so, Ta Oyate Duta stood and boldly signed the treaty followed by Wabasha III and sixty-three other leaders.

Sibley tried to get the Mdewakanton and Wahpekute to sign traders' papers, but both bands initially refused. Eventually, in November 1851, leaders from the two bands did so. Some sources suggest that tribal leaders and their agents were bribed into signing the papers. The Wahpekute agreed to pay traders $90,000. The Mdewakanton paid $70,000 and were given $20,000 which was shared between seven chiefs. Five Dakota men were also released from the jail at Fort Snelling when the papers were signed. The Treaty of Mendota stated that there would always be friendship between the Dakota and United States Government. The Dakota were to receive $1,410,000 for their land, most of which would be held in trust and paid in annual annuities.

The treaties with the Dakota were approved by Congress, with some changes, on June 23, 1852. Forty-five chiefs of the lower bands signed the treaty on September 4, 1852. With the treaty, Ramsey and other government officials accomplished one of their greatest goals. Sibley and the traders received some money, though not all of the Dakota's debts were paid. The Dakota ceded much of their homeland with the treaties of 1851, and began living on reservations, which was a permanent change to their way of life.