Salazar said his department is currently consulting with state agencies, including the state historic preservation office, and the final decision will be made "hopefully by the end of this year.
"There is a legal process," Salazar told reporters outside a White House conference on developing a clean energy economy. "I have ordered my department to move forward with the expeditious conclusion of those processes."
The Cape Wind project in 2001 became the country's first major proposed offshore wind farm. Its developers, Cape Wind Associates LLC, aim to construct 130 towers, which will tower 440 feet above the surface of the Nantucket Sound.
Interior's Minerals Management Service gave Cape Wind a favorable environmental review at the start of this year, finding that there would be little negative impact from the project.
The proposed $1 billion wind farm is designed to power about 400,000 homes, but would be within view of popular Cape Cod resorts.
The project has faced serious opposition from business leaders and politicians, including the late Senator Edward Kennedy. Opponents say the turbines would be an eyesore on the pristine area and threaten the tourist industry around Cape Cod, Martha's Vineyard and Nantucket.
The decision on the wind farm has also been held up by local native tribes who have requested that the area where the project would be located be designated a "traditional cultural property."
Supporters of the project, including Massachusetts Governor Deval Patrick and many environmental groups, have said it would create needed jobs and cut air pollution and greenhouse gas emissions.