Bishop Henry B. Whipple lays the cornerstone for the Cathedral of Our Merciful Savior in Faribault, the first Episcopalian cathedral built in the United States. On the following day Whipple sets the cornerstone of the nearby Seabury Divinity School. The cathedral is dedicated on June 24, 1869.

The city of Kinney, St. Louis County, secedes from the United States. The city council, frustrated by unsuccessful attempts to obtain a grant from the federal government for a water project, decides to secede and apply for foreign aid because "there is less paperwork." Passports are issued by sympathizers in New Haven, Connecticut. Although the United States did not recognize Kinney as a foreign country, Duluth's frozen food king Jeno Paulucci did, giving Kinney a used Ford to replace the city police car (which no longer ran) and ten cases of frozen pizza for good measure.

The steamer Sea Wing, carrying a large party and towing a barge, capsizes in a sudden storm on Lake Pepin. Twenty-five individuals manage to clamber back on the boat, but, a few hours later, the boat turns turtle again, throwing the survivors back in the water. By the time the boat and the barge are driven ashore, ninety-eight individuals had drowned. Surprisingly, no one on the barge was hurt.

Faribault begins requiring dog licenses.

The Third Minnesota Infantry Regiment suffers one of the great embarrassments of the Civil War when it surrenders to a smaller Confederate force led by Nathan Bedford Forrest, who convinced the Minnesotans that his force was much larger than theirs. The men would be paroled and eventually return to action, fighting well under new officers.

Ozaawindib (Yellow Head), an Ojibwe leader and agokwa, shows Henry Rowe Schoolcraft that Lake Itasca is the source of the Mississippi River. Schoolcraft would name the lake from the Latin words veritas caput (truth head), using the last syllable of veritas and the first of caput. The Ojibwe name for the lake is Omushkos (Elk Lake).

Congress passes the Northwest Ordinance. Authored by Thomas Jefferson, it set up the rules of government for the Northwest Territory of the United States, which included present-day Minnesota east of the Mississippi River. Slavery was outlawed, the land was to be surveyed into townships, and each township was to set aside land for a school. In addition, the ordinance stated that "the utmost good faith shall always be observed toward the Indians, their land and property."

The Minnesota Twins retire number 6, formerly worn by slugger Tony Oliva, who was 1964 American League Rookie of the Year and three-time American League batting champion.

Lawrence S. Donaldson, founder of the first department store in the "Northwest," dies in Minneapolis.

Four Minnesota regiments finally defeat their old nemesis, Nathan Bedford Forrest, in battle at Tupelo, Mississippi. The Seventh Minnesota Regiment plays the largest role and loses sixty-two men. Colonel Alexander Wilkin of the Ninth Minnesota Regiment is killed, making him Minnesota's highest-ranking casualty in the Civil War.