Colonel Henry Leavenworth performs a marriage ceremony for Lieutenant Green, one of the officers at Fort St. Anthony (later called Fort Snelling), and a woman named Miss Gooding. Leavenworth has legal authority to perform marriages not as post commander, but as Indian agent for the lands east of the Mississippi, so he and the couple cross the river for the ceremony.

The US Senate votes 96-0 to denounce David Durenberger for "reprehensible" conduct as a senator, making him one of only seven members to be publicly condemned by the Senate in the twentieth century. Durenberger is censured for financial misconduct, including evading the limit on outside earnings.

In New Ulm, a group of at least 6,000 attends a rally at Turner Park to protest the policy of sending draftees of German descent to fight in World War I.

A Baptist church in St. Paul holds Minnesota's first known Sunday school session.

Princeton-area farmer O. J. Odegard is the first to utilize the labor of Axis prisoners of war when he requests 100 Italian POWs for farm work due to the acute labor shortage in Mille Lacs County. Odegard is forced to pay the average wage for farm work, $3.00 per prisoner per day, and the prisoners and forty armed guards arrive from Camp Clark, Missouri, on September 5. Provided with kitchen facilities, the prisoners prepare their own food, and, in fact, they are such skilled cooks that their guards prefer their meals over standard army fare.

St. Paul's horse-drawn fire engines make their final run.

A mob attacks the Brainerd jail, where two Ojibwe brothers, Te-be-ke-ke-sheck-wabe and Go-go-once, are being held for allegedly murdering a woman. The men are taken to a nearby pine tree and hanged in front of a crowd of 1,000. After the lynching, a rumor spreads among Brainerd's residents that angry Ojibwe are planning to attack the town. Sheriff John Gurrell telegraphs Governor Horace Austin for help. Three companies of troops are sent out, arriving on July 25.

The Sisseton and Wapheton Dakota sign the Treaty of Traverse des Sioux, near St. Peter. Maḣpiya Wic̣aṡṭa (Cloud Man) and Iṡtaḣba (Sleepy Eye) are among the Dakota signers, while Alexander Ramsey and Luke Lea represent the United States, with missionary Stephen Riggs interpreting.

Father Francis Pierz, a Slovene priest, arrives at his post in Grand Portage. He remains there for a few months and then returns in 1841 to establish a mission on the Pigeon River. His later writings encourage Germans and Slovenes to immigrate to the "earthly paradise of Minnesota."

Geographer Joseph N. Nicollet is born in France. After traveling by canoe to Omashkoozo-zaaga'igan (later called Lake Itasca) in 1836 and to Inyan Sa K'api, a pipestone quarry sacred to Dakota people, in 1838, he published a map of the upper Mississippi River's drainage system in 1843.