Cyn ei ymweliad, mynegodd y Prif Weinidog y dylai'r berthynas arbennig fod yn sail i gael gwared â rhwystrau ac i roi hwb i fasnach rhwng Cymru a'r Unol Daleithiau.
Ahead of the visit, the First Minister is calling on the special relationship to be a vehicle for removing barriers and boosting trade between Wales and the USA.