From D-Day to 21 August, the Allies landed 2,052,299 men in northern France. The cost of the Normandy campaign was high for both sides. Between 6 June and the end of August, the American armies suffered 124,394 casualties, of which 20,668 were killed. Casualties within the First Canadian and Second British Armies are placed at 83,045: 15,995 killed, 57,996 wounded, and 9,054 missing. Of these, Canadian losses amounted to 18,444, with 5,021 killed in action.

Battle, Siege, or Offensive Conflict

Estimated number of Americans killed

Battle of Normandy World War II June 6 to August 30, 1944 - 29,204 killed

Battle of Okinawa World War II April 1 June 21, 1945 - 20,195 killed

Battle of the Bulge World War II December 16, 1944, to January 25, 1945 - 19,276 killed

Battle of Hürtgen Forest World War II September 19, 1944, to February 10, 1945 - Over 12,000 killed

More Info: en.wikipedia.org