Gov. John Baldacci on Monday announced the completion of a decade-old preservation effort for “the most beautiful spot in the world” – a 50-mile stretch of St. Croix River and Spednic Lake shoreline in northern Washington County between Baileyville and Danforth.

Conservation efforts along the river, which forms the border between Maine and New Brunswick, began a decade ago when leaders pledged to cooperate on St. Croix preservation projects.

“It has taken a long time, but it’s finally done,” said Elizabeth Swain of the New England Forestry Foundation.

The project’s 3,000 acres, which were owned by a group of investors and managed by New Hampshire-based Wagner Land Management Co., have been purchased by the foundation for $2.5 million in private and public money, and donated to the state. The deal was completed on March 20.

“It will belong to the public, as well it should,” Swain said.

The project includes a 500-foot strip of forested land along 34 miles of the upper St. Croix and 16 miles of Spednic Lake, as well as several small islands.

About 20 miles of Spednic shoreline previously had been preserved by the local Woodie Wheaton Land Trust and the St. Croix International Waterway Commission.

The land trust, primarily made up of local anglers, started the project and nurtured it all the way through but chose to partner with the New England Forestry Foundation when its scope outgrew its founders, explained Dale Wheaton of the Woodie Wheaton Land Trust.

Half a million acres already have been conserved on the Canadian side of the river, including most of the shore.

“They got a head start on us,” Swain said.

In Maine, the Department of Conservation’s Bureau of Land Management will take responsibility for the river shore, which is a major recreational resource. More than 5,000 people canoe the upper St. Croix each year, and campgrounds and boat launches dot the shore.

The Department of Inland Fisheries and Wildlife will manage the lakeshore, which is an important wildlife habitat. Maine’s bald eagle restoration program began in the area, and the federally protected birds often are spotted fishing in the waterway.

Federally endangered Atlantic salmon also live in the St. Croix River.

The $2.5 million deal is composed of $1.43 million from the state Land for Maine’s Future bond money, $175,000 in federal conservation funds and $50,000 from the Maine Outdoor Heritage Fund.

About a million dollars in private funds from more than 300 donors was raised by the New England Forestry Foundation. The Woodie Wheaton Land Trust raised $120,000 of that.

“In these tough economic times, it is particularly gratifying,” said Amos Eno, executive director of the foundation. “We’ve been blessed with outstanding partners.”

“This is how things get done – a lot of effort by a lot of people,” the governor added.