The mission, organised by Hybu Cig Cymru - Meat Promotion Wales (HCC) and led by Wales’ Minister for Natural Resources and Food, Alun Davies, revealed an "overwhelmingly postitive" response from United States officials over plans to ship PGI protected Welsh Lamb into the country.
HCC chief executive Gwyn Howells said: "The series of meetings we had with leading officials from the United States Agriculture Department and other North American meat organisations were overwhelmingly positive."
He said the opportunities for Welsh meat suppliers in the US market were "enormous" and that exports to the States could be worth £20m a year to farmers and processors.
The opening of the US market to beef from Europe meant it was important that lamb was also allowed in, he added: "The stumbling block until now has been the question of Transmissible Spongiform Encephalopathy, or TSEs, which manifests itself as scrapie in sheep. Extensive research undertaken by the World Organisation for Animal Health (OIE) has shown that while scrapie is present in some sheep, it poses absolutely no risk whatsoever to human health.
"During our meetings the USDA accepted the OIE’s evidence that TSEs do not pose any risk to human health."
Laura Dodds, HCC’s Market Development Manager, said the mission also showed how the Welsh meat board could help stimulate demand for lamb generally in the US market.
"In light of the decline of the domestic lamb industry in the US – which now has just 5.34 million head of sheep compared with Wales’ nine million – our position was warmly welcomed by the USDA, the North America Meat Association, the Meat Import Council of America and the Tri Nations lamb group."
The mission also visited Canada, which has been open to Welsh Lamb for the past two years. Dodds said there was strong demand for product in the high end retail and hotel sector in Canada, and they were looking to expand Wales reach from eastern Canada into the west of the country.