United States Army
From Memory Alpha, the free Star Trek reference.
The United States Army was the land-based branch of the United States armed forces.
During the 19th century, the Army was known as the Union Army, during the American Civil War.
The Union Army utilized observation balloons that were tendered at around six hundred feet high. (TOS: "The Savage Curtain")
Among the campaigns the Union Army engaged in during the Civil War include Battle of Pine Mountain, part of Sherman's March to the Sea. (VOY: "Death Wish")
The United States Army was deployed on several fronts when the Allies invaded Nazi-occupied France during World War II. (VOY: "The Killing Game", "The Killing Game, Part II")
