The USS Lexington was located at a depth of about 3km (2 miles) in the Coral Sea, about 800km off Australia's east coast.
The ship was lost in the Battle of the Coral Sea from 4-8 May 1942. More than 200 crew members died in the fighting.
The US Navy confirmed the ship had been discovered by a search team led by Microsoft co-founder Paul Allen.
Pictures showed the wreck to be well preserved.
The US Navy said 216 crew members died after the ship was attacked. More than 2,000 others were rescued.
"Lexington was on our priority list because she was one of the capital ships that was lost during WWII," Vulcan spokesman Robert Kraft said.
Pictures from the seabed taken by the Petrel show the Lexington's nameplate and guns. Some of the ship's aircraft are also shown in remarkably good condition.