The company said the a2 Milk brand had been accepted by a number of major retailers in this region including Ahold, Shoprite, Safeway, H-Mart and Fairway Foods.
A2 said it aleady had a growing presence in the natural foods channel in this region through Wholefoods, Sprouts and The Fresh Market.
The expansion in distribution would be supported by increased marketing investment behind the "Love Milk A gain" advertising campaign.
The cost of the expansion in the US was incorporated in the forecasted higher marketing expense for the group in second half of its financial year, relative to the first half, as advised at annual meeting in November last year.
A2, which last year year surpassed Fletcher Building and a clutch of other market heavyweights in terms of market capitalisation, said it was also investigating specific new product opportunities for the US market to further capitalise on growing brand awareness and distribution.
Late last year, a2 announced that former Jetstar group executive Jayne Hrdlicka would take over from Geoff Babidge as chief executive.
The company's shares closed on Tuesday at $8.00, having rallied by $5.69 or 246.32 per cent over the last 12 months.