And also consider the Battle of Antietam (or Sharpsburg, if you prefer
) during the American Civil War:
Union casualties in killed, wounded, and captured/missing were 2100, 9550, and 750, respectively, for a total of 12400.
Confederate casualties in the same categories 1550, 7750, and 1020, respectively, for a total of 10320.
Total battle casualties were 3650, 17300, and 1770, respectively, for a grand total of 22720 Americans killed, wounded, or captured/missing.
Generally regarded as the single bloodiest day of the war, this carnage was achieved in about 12 hours of fighting. It works out to be almost 1900 casualties per hour.
I echo John's and Nash's sentiments -- regardless of time period or conflict, one loss is too many.