Stretching 35km along the shore of Lake Hawea into the Hunter Valley and surrounded by mountains and native bush, the station has been described as one of the most picturesque in New Zealand.
Scenes for the Disney film A Wrinkle In Time staring Reese Witherspoon and Oprah Winfrey were shot at the station last week.
The Cochranes could not be contacted yesterday.
In the OIO's decision summary the buyer is listed as being 100 per cent American with Orange Lakes (NZ) Ltd listed as the consent holder in the purchase.
On the Companies Office register Orange Lake's director is named as Queenstown accountant Craig Benington, head of accountancy firm Crowe Horwath Queenstown.
In an online profile, Benington says he has advised many overseas investors on taxation and compliance issues and has experience with foreign investment and knowledge of international tax laws.
Benington did not return calls yesterday.
In its decision, the OIO said the buyer would continue to farm sheep and cattle on the property and intended to invest capital in the farm to significantly enhance its production.
There was also a willingness from the buyer to enable public access to several important sites in or near the station.
Public access to parts of the station has been a contentious issue in the past. In 2015 the Cochranes temporarily blocked access to a road which provides the only road access to the Department of Conservation's Kidds Bush camp.
Access to five huts on the land, some used by the same family for more than 50 years, was also blocked.
Hut owner Drybread farmer Tony Glassford said he had heard rumours an American businessman had bought the station but had not been contacted by anyone to discuss access.
He was hopeful the new leasee would be willing to negotiate access to the hut and planned to approach the new owner.
Overseas ownership of land near Wanaka was highlighted after it was revealed American billionaire Peter Thiel bought 193ha of farmland near Glendhu Bay in 2015.
Two other high country stations in the Upper Clutha, Lake Hawea Station and Lake McKay, are also in the process of being sold.