A snowstorm covers Duluth on this day and the next. Many people must exit their houses through second-story windows.

Douglas County is formed. Its name honors Stephen A. Douglas of Illinois, who advocated for Minnesota's statehood.

Early this morning, a plainclothes policeman is beaten and thrown out of a room at the St. Paul Hotel, where members of the state legislature and their friends are said to be playing cards. The officer returns with six more plainclothes men and "exciting scenes" follow, including the flight through a window into another room by a man who had hit the first policeman with his fist.

The Minnesota State Butter and Cheese Association is organized in Rochester. The group promotes dairy farming in the state and counts among its successes the "grand sweepstakes" award for the best butter at the 1885 World Industrial and Centennial Exposition in New Orleans.

Duluth becomes the first city in the nation to ban the sale of mercury thermometers (to prevent the element from polluting the environment). Minnesota had prohibited use of mercury thermometers in hospitals in 1992.

The name Lac qui Parle is given to a new county. The name, French for "lake that talks," likely refers to echoes among the bluffs surrounding the lake of the same name and comes from the Dakota place name (Mde Iaúdaŋ, Small Lake That Speaks) that predates it. Yellow Medicine County is also formed, named for the root of the moonseed, called pejuta zi (yellow medicine) by Dakota people and used as a medicinal herb.

Grant, Lyon, and Wilkin Counties are formed out of Lac qui Parle County, which ceases to exist (see March 6, 1871). Grant and Lyon are named for Civil War Generals Ulysses S. Grant and Nathaniel Lyon. Wilkin County had previously been named for Robert Toombs, who later became a Confederate leader. The county was then named Andy Johnson, for the president, but his political attitude disturbed the county's residents, leading them to adopt the present name, which honors Colonel Alexander Wilkin.

Henry B. Whipple, the Episcopal bishop of Minnesota, writes a letter to President Abraham Lincoln on behalf of the Dakota people of the state, describing corruption among agents of the US Bureau of Indian Affairs and asking for "justice for a wronged and neglected race." The US–Dakota War of 1862 began in Minnesota later that year.

The US Supreme Court delivers the Dred Scott decision, in which the justices declare that enslaved Missouri man Dred Scott, not being a citizen, has no right to bring suit. Scott had lived at Fort Snelling and in other "free" areas with his owner, Dr. John Emerson, and he claimed that residence in free states and territories made him a free man.

Hennepin County is formed, named for Louis Hennepin, the Franciscan missionary who saw and named the Falls of St. Anthony in 1680.