In what port city did u. s. marines make a surprise amphibious counterattack during the korean war?
incheon
pusan
pyongyang
yalu

It was at Incheon during the Korean War. It took place from September 15, 1950 to September 19, 1950 under the code name Operation Chromite. It was an important victory for the United Nations that in taking the capital of Seoul that with 75,000 troops and 261 naval ships.  The attacked finished a series of victories by the North Korean People’s Army and cut its supply lines in South Korea.  The attack was encouraged by General Douglas MacArthur despite hesitations of other generals.