A record 66 American troops have died so far, eclipsing the 65 killed in July 2010.
This month's death toll soared when 30 Americans, most of them elite Navy SEALs, were killed in a helicopter crash Aug. 6.
Aside from the Chinook crash, 23 died this month in Kandahar and Helmand provinces in southern Afghanistan and the remaining 13 were killed in eastern Afghanistan.
Violence is being reported across Afghanistan despite the U.S.-led coalition's drive to rout insurgents from their strongholds in the south.
On Tuesday, Afghanistan President Hamid Karzai urged insurgents to lay down their arms and help rebuild the nation.
The military has begun to implement President Barack Obama's order to withdraw the 33,000 extra troops he dispatched to the war. He ordered 10,000 out this year and another 23,000 withdrawn by the summer of 2012, leaving about 68,000 U.S. troops on the ground.
Afghan has set the end of 2014 as the target date for Afghan police and soldiers to take the lead in protecting and defending the country, leaving international combat forces to go home or take on more support roles.
So far this year, 403 international service members, including at least 299 Americans, have been killed in Afghanistan.
The Associated Press contributed to this story.