Energy firm NaiKun said the site off Canada's west coast could support up to 400MW of capacity in the first phase of the project.
The Haida Energy Field will be located in the Hecate Strait between the Haida Gwaii islands and the port city of Prince Rupert on the Pacific Ocean coastline, the Danish developer said.
Dong said the shallow waters of around 15 metres would allow fixed-bottom turbines. Average wind speeds at the site have been measured at 10m/s.
According to NaiKun, the site has environmental assessment certificates in place from provincial and federal governments. It is still waiting for a power off-take deal.
The whole area could support up to 2GW of offshore wind if fully developed over several phases.
"This agreement effectively connects the largest offshore wind developer in the world with a project that offers one of the strongest, most-consistent wind resources in the world," said Naikun CEO Michael O'Connor.
It is Dong's first move into the Canadian offshore wind market, having secured rights for two offshore wind projects in the US and acting as a strategic partner for a third.
"Offshore wind is a reliable homegrown energy source, and we are excited to explore the Canadian market," said Dong's North American president, Thomas Brostrom.
"We see this opportunity as a first step to bringing offshore wind power to Canada in what could become a strategic partnership with the nation's front-runner project." he added.
Under the letter of intent, Dong and NaiKun would also "explore the potential for establishing a long-term partnership".
In 2013, Windpower Offshore reported a preferred supplier agreement was in place with Siemens to provide its 4MW turbine to the project. The agreement is still in place, but a larger turbine could be used.