Assistant Secretary of State for East Asian and Pacific Affairs Daniel Russel toured the islands alongside the Commander of the US Pacific Fleet, Admiral Scott Swift.
Mr Russel said the visit symbolised the whole-of-government approach to enhancing relations in the area.
"It's an integral part of American strategy and has been for many decades. I'm proud to say that over the last seven years we've really deepened our engagement and intensified our engagement in the affairs of the Pacific."
The delegation met local government officials and visited USAID projects.
In Palau, Mr Russel met with the leaders of Palau, the Marshall Islands and the Federated States of Micronesia and addressed of the local legislature.