Locals said the camps, both in Bayda province, were named after prominent ISIS figures: Yemen chief Abu Bilal al-Harbi and former global spokesman Abu Mohamed al-Adnani, killed last summer in a USA air strike.
A United States defense official told CNN this is the first USA strike specifically targeting ISIS in Yemen.
Gen. Joseph Votel approved the strike under existing counterterrorism authorities.
"ISIS has used the ungoverned spaces of Yemen to plot, direct, instigate, resource and recruit for attacks against America and its allies around the world", said the Pentagon statement.
The Pentagon said the ISIS camps - located in Al Bayda Governorate, Yemen - were used to "train militants to conduct terror attacks using AK-47s, machine guns, rocket-propelled grenade launchers and endurance training".
Yemen's minority Houthis, who are Shiite, rebelled against the Sunni-led government, backed by Saudi Arabia.
The US air raids coincided with ongoing anti-terror military operations carried out by newly-trained Yemeni troops against Yemen's al-Qaeda branch, known as al-Qaeda in the Arabian Peninsula (AQAP) in Abyan.
The UN statistics showed that over 8,000 people, a lot of them civilians, have been killed in Yemen's conflict since the Saudi-led coalition entered the conflict in 2015.
Several hideouts of the Yemen-based al-Qaeda branch were hit by a series of airstrikes launched by U.S. drones in the central province of al-Bayda, a military official said.
The conflict has spurred one of the greatest humanitarian crises to befall the region, with 7 in 10 Yemenis needing assistance because of the conflict and a subsequent cholera outbreak in the region, according to Save the Children.