In a letter to the US Ambassador to the United Kingdom, Mr Louis B. Susman, the First Minister set out the importance of the relationship between the two countries.
The First Minister said:
"My best wishes to you and our American friends as you celebrate the 4th July, such a pivotal event in the history of your country.
"Welsh links with America go back to the signing of the Declaration of Independence and beyond, some would say to the discovery of America by Welsh explorer Madog.
"As the chapters of your history have been written, Welsh-Americans have played a central role in the story of your nation.
"Today we greatly value the business, education and cultural links between our two countries. Our trade links are invaluable, with the US representing the largest single export market for Wales.
"There are currently more than 200 US business operations and initiatives here in Wales, such as the Wales Fulbright Summer Institute giving young leaders of the future a connection with Wales which we hope will provide an opportunity for these students to find out more about Wales’ proud heritage and our position as a modern nation within the UK and the wider world.
"On behalf of the people of Wales, happy Independence Day."
In May this year the First Minister led a trade mission to the USA to expand Wales’ links with the country. Later this year there will be a Welsh Government led trade missions to Los Angeles, San Francisco, Boston, Washington and Chicago.