Halvor Langdon Halvorson (July 15, 1881 – October 3, 1951) was an American politician and attorney who served as the mayor of Minot, North Dakota and later became a perennial candidate in North Dakota's congressional elections.

On August 15, 1881, Halvor Langdon Halvorson was born in Henning, Minnesota. In 1902, he graduated from the University of North Dakota with a law degree and in 1908, moved to Minot, North Dakota.^[2]

In 1910, he ran for state treasurer against incumbent Republican Gunder Olson and in September was named as vice chairman of the state Democratic party, but was defeated.^[3][4] Following the resignation of former Commission President Arthur LeSueur on May 17, 1911, a special election was held on June 6, in which Halvorson narrowly defeated Dorr H. Carroll and Peter Vandenoever with 232 votes against 196 and 94 votes.^[5] In 1912, 1914, and 1918, Halvorson ran for North Dakota's third House district, but lost each time with his best showing being 31.16%.^[6][7][8] He served as a delegate to the 1916 Democratic National Convention and gave his support to incumbent President Woodrow Wilson.^[9]

In 1916, Halvorson attempted to win the Democratic nomination for governor, but was defeated by D. H. McArthur who went on to lose in a landslide to Lynn Frazier.^[10] In 1924, he narrowly defeated L. S. Platon for the Democratic gubernatorial nomination with 6,020 votes to 5,244 votes and was narrowly defeated by Arthur G. Sorlie with 53.93% to 46.07% of the vote.^[11][12][13]

In 1932 and 1938, he attempted to win the Democratic nomination for Senator, but was defeated both times.^[14][15] In 1940, he won the Democratic nomination for attorney general and was narrowly defeated by incumbent Alvin C. Strutz with 52.19% to 47.81% of the vote.^[16] In 1942 and 1944, he ran for North Dakota's at-large congressional district, but was defeated both times although he was the best performing Democrat both times.^[17][18]

In 1949, he was one of the attorneys who advised the Turtle Mountain Band of Chippewa Indians in their $24,000,000 claim against the federal government.^[19] On October 3, 1951, he died in a Minot hospital after being there since June 26 due to pneumonia and a heart condition.^[20]