The United States acquired vast western territories as part of the Louisiana Purchase, including the future state of North Dakota.
Congress created the Dakota Territory, which consisted of the present-day states of North Dakota and South Dakota and most of Montana and Wyoming.
President Grover Cleveland signed legislation authorizing North Dakota, South Dakota, Montana, and Washington to be organized as states.
President Benjamin Harrison signed the formal proclamation admitting North Dakota as the 39th state in the Union.
Lyman Casey of Jamestown and Gilbert A. Pierce of Fargo presented their credentials and took the oath of office as North Dakota's first senators. The senators then drew lots to determine their class assignments. Casey drew Class 1, with a term to expire March 3, 1893. Pierce drew Class 3, with a term to expire March 3, 1891.
Senate Republicans called for an investigation of Senator William Roach of Larimore, a newly elected Democrat, after newspaper accounts accused him of having once embezzled funds while working as a bank teller. The Senate declined to investigate the charge.
Porter J. McCumber of Wahpeton became chairman of the Senate Committee on Manufactures (today's Committee on Commerce, Science, and Transportation), serving until 1903.
Senator Porter J. McCumber became chairman of the Committee on Pensions (now the Committee on Health, Education, Labor, and Pensions), serving until 1913.
Senator Fountain L. Thompson, who had just been appointed a senator in December 1909, unexpectedly resigned for reasons of ill-health. Senator Porter J. McCumber announced that a man seated in the rear of the chamber, William E. Purcell of Wahpeton, held a certificate of appointment as Thompson's successor. Surprised senators complained that they had heard nothing of his appointment until then, but permitted him to take the oath as a senator.
Former senator Henry Clay Hansbrough published a novel, The Second Amendment (Minneapolis: The Hudson Publishing Company), set in the U.S. Senate and involving the formation of an "Altrucratic Party."
Senator Porter J. McCumber engaged in a tempestuous debate with Senator James A. Reed, a Missouri Democrat, over a soldiers' bonus bill. The debate concluded with McCumber offering to settle their differences "outside." The following day's Congressional Record deleted most of the angry exchange.
President Coolidge signed into law the Fordney-McCumber tariff, sponsored by Senator Porter J. McCumber, which significantly raised tariff rates, reflecting a post-World War I shift toward isolationism.
Senate Republicans announced that they would deny seniority and committee chairmanships to Senator Edwin Ladd of Fargo and other senators who bolted from the Republican Party to endorse Robert F. La Follette's Progressive Party presidential campaign in 1924.
Senator Edwin Ladd died before regaining seniority that his party conference had removed; other penalized senators had their seniority reinstated when Congress convened in December.
The Senate voted to seat Gerald P. Nye of Cooperstown, who had been appointed to fill the vacancy created by Senator Ladd’s death, despite the unfavorable report by the Committee on Privileges and Elections.
President Franklin D. Roosevelt signed the Frazier-Lempke Farm Bankruptcy Act, sponsored by North Dakota senator Lynn J. Frazier of Hoople and representative William Lemke of Fargo, designed to prevent farm foreclosures. In 1935 the Supreme Court declared the act unconstitutional in the case of Louisville Joint Stock Land Bank v. Radford.
The Special Committee on Investigations of the Munitions Industry began hearings, giving its chairman, Senator Gerald P. Nye, national attention. The committee accused arms manufacturers of being "merchants of death" that induced the United States to enter World War I. Nye's investigation led to neutrality legislation designed to keep the United States out of another European war.
In response to the Supreme Court's striking down the original law, Congress passed a new Frazier-Lemke bill that established a three-year moratorium on farm mortgage foreclosures.
The Senate seated William "Wild Bill" Langer of Bismarck without prejudice after receiving a petition from residents of North Dakota charging him with corruption. After a year's investigation, the Senate Committee on Privileges and Elections recommended against him, but on March 27, 1942, the Senate voted 30 to 52 not to deny him his seat.
North Dakota farmer Milton R. Young of Berlin took the oath as a senator, having been appointed to fill the vacancy caused by the death of Senator John Moses of Hazen. Young spent more than 35 years in the Senate, the longest service of any North Dakota senator.
Senator William Langer collapsed in the chamber during an all-night session of the Senate dealing with President Truman's veto of a Communist registration bill. He later recovered.
Due to age and ill health, Senator William R. Langer was unable to return to North Dakota to campaign for reelection and relied on mailings instead. He won with 57 percent of the vote.
A bronze statue of John Burke, former governor and secretary of the treasury under Woodrow Wilson, was unveiled in the Capitol as North Dakota's first contribution to the National Statuary Hall Collection.
Senator Quentin Burdick died after serving 32 years in the Senate, the second-longest of any North Dakota senator. His widow Jocelyn Burdick was appointed to succeed him, becoming the state's first woman senator. She was not a candidate for reelection.
Heidi Heitkamp of Mandan became the first woman elected to represent North Dakota in the United States Senate.