If you mean what war had the most US casualties is was the Civil War, over 700,000. More than other wars that have happened since combined.
The families of those killed in the war suffered the most.
See website: Statistics About the Vietnam War.
At least 816,000 americans got killed
sorry, but i do know that 50,000 Americans were killed in the Korean War.
There was actually never a war between cowboys and Natives Americans. Most Native Americans were killed by the US military. Eventually, the military won and Native Americans were forced onto reservations.
This question is a bit unclear. If you are referring to the Korean war, 36,516 Americans were killed in that war. If you are referring to World War II, 418.500 Americans were killed in that war.
Probably the Civil War was because the most Americans killed in any war was our own Civil War fought between the Northern and Southern states between 1861 - 1865.
'56.
About 35 Paiute Indians (native Americans) were killed during the Pyramid Lake War in 1860.
I think about 25,700 Americans killed, and 10,000 British killed.
If restricted to the War Between the States, it would be the Battle of Gettysburg where over 7800 Americans were killed. If not restricted, it would be the WW I Battle of the Argonne Forest where over 26,000 American solders were killed. The most killed in one day in any war would be at the Battle of Sharpsburg (also called the Battle of Antietam) where over 3600 were killed.
Since Americans were killing Americans, it was the US Civil War (aka American Civil War).