A spectacular stretch of Northern California coastline that includes ocean-side bluffs, beaches, rolling hills and redwood groves will be permanently protected from development under a landmark deal approved by the state Coastal Commission.

Nearly 10 square miles of untouched shoreline, wooded glens, streams and farmland in northern Santa Cruz County, extending several miles inland, will be transferred to the state and federal governments, which will operate it as open space and preserve portions for agriculture.

Much of the land, known as the Coast Dairies ranch, will ultimately be opened to the public.

One commissioner said that by protecting the coastal land and targeting nearby parcels for conservation, the state may be on its way toward forming a West Coast equivalent of the Adirondacks, the vast public-private patchwork of mountains, forests and waterways in New York state.

The coastal panel’s unanimous vote at a meeting Thursday in Ventura protects 71/2 miles of coastline that had been one of the three largest pieces of private coastal property between the Golden Gate Bridge and the Mexican border, according to the agency.

The expanse of former Spanish land grants was acquired by Swiss farming families in the 1860s and purchased by the Trust For Public Land in 1998 as rumors swirled that developers had plans to bulldoze some of the property and build homes.

“This is important: an incredible part of the Central California coast that’s going to be retained in the form it was years and years ago,” said Dan Carl, the commission’s Central Coast District director. “It’s something you don’t see a lot in California as development moves and marches forward.”

The deal to safeguard the land, in the works for more than a decade, was praised as embodying California’s stringent coastal protection law.

It comes 40 years after the passage of Proposition 20, the 1972 voter-approved initiative that created the California Coastal Commission and gave it control over development along the state’s 1,100-mile coastline. That authority was cemented by the 1976 state Coastal Act.

“This really is a reflection of 40 years of work,” said Charles Lester, the commission’s executive director. “The Coastal Act played a fundamental role in making these types of acquisitions possible.”

The decision came at the commission’s first meeting since the April 1 death of its longtime executive, Peter Douglas, whose decades of leading the agency through high-profile conservation battles is credited with keeping much of the California coast from being paved over.

To keep that from happening to the Coast Dairies ranch, the commission limited use of the land to public recreation, open space and agriculture.

The arrangement transfers upland portions of the property, which reaches about 21/2 miles inland and surrounds the tiny coastal town of Davenport, to the federal Bureau of Land Management.

It also includes 400 acres of shoreline along California 1 that has already been deeded to the state Department of Parks and Recreation, which operates adjacent Wilder Ranch State Park. About 700 acres will remain under ownership of the Trust For Public Land for use as farmland, including organic strawberry fields.

“What’s particularly unique,” said Sam Hodder, the Trust For Public Land’s California state director, “is having such a vast expanse of remarkable resources, from recreational opportunities to critical habitat, sweeping ocean views, to iconic scenic character, all so close to where people live, work and play.”

Coastal Commissioner Steve Blank summed up the decision: “We all win here. The people of California win.”

tony.barboza@latimes.com