Andrew Christian Tychsen (June 27, 1893 – July 3, 1986) was a United States Army officer with the rank of Brigadier General.
Tychsen was born on June 27, 1893 in Hoboken, New Jersey. During World War I, Tychsen enlisted as a Private in the Minnesota National Guard in April 1914 and was assigned to Company A of the 1st Infantry. In this capacity, Tychsen served on Mexican Border during Pancho Villa Expedition. He rose to the rank of First sergeant and was posted to the First Reserve Officers Training Camp at Fort Snelling on March 25, 1917.
Since August 1917, Tychsen was deployed in France with 88th Infantry Division and participated in the combats near Belfort and Epinal. Tychsen was promoted to the rank of Captain and Commanding Officer of Company C, 339th Machine Gun Battalion.
After his return to the States in 1919, Tychsen was commissioned as a Captain in the Regular army and attended the United States Army Infantry School at Fort Benning in 1921. During 1921–1925, he served as Assistant Professor of Military Science and Tactics at University of Minnesota.
Subsequently he served as Professor of Military Science and Tactics at St. Thomas Military Academy until 1932, when he was transferred to Hawaii, where he served at Schofield Barracks with 27th Infantry Regiment.
On August 1, 1935 Tychsen was promoted to the rank of Major and was detached to the Command and General Staff School at Fort Leavenworth in Kansas. He graduated there a year later and then was transferred to Jefferson Barracks in Missouri, where he served with 6th Infantry Regiment until 1938.
During the year 1938, Tychsen was transferred to the Camden, New Jersey, where he was appointed as an Executive officer of the Camden Military District. In this capacity, he was in command of Organized Reserves.
He spent some time as a Battalion commander of the 1st Infantry Replacement Group, before took command of 399th Infantry Regiment within 100th Infantry Division. He participated in the Battle of the Bulge, Rhineland Campaign and Central European Campaign.
At the beginning of January 1945, Tychsen was appointed assistant division commander of 100th Infantry Division. He succeeded Brigadier General John S. Winn in this capacity. He was promoted to the rank of Brigadier General on April 12, 1945.
On August 22, Tychsen succeeded Major general Withers A. Burress as Division commander and served with the Division until the end of January 1946, when the Division was inactivated.
During Korean War, Tychsen was appointed as Chief of Staff of the IX Corps under command of Major general Willard G. Wyman. Brigadier general Tychsen retired from the Army on June 30, 1953.
After retirement from the Army, Tychsen served on the United Nations Rehabilitation Commission for Korea and finally retired in 1958. Brigadier general Andrew Christian Tychsen died at the age of 93 on July 3, 1986. He is buried at Arlington National Cemetery.