LOS ANGELES - State agencies and conservation groups announced a tentative deal Friday to bar housing development on virtually all 82,000 acres of the Hearst Ranch, a stretch of coastal land that many consider among the most beautiful and threatened in California.

The deal, which will require public meetings before approval, calls for the Hearst Corp. to sell 1,500 acres of oceanfront land between Los Angeles and San Francisco to the state for $80 million in cash and $15 million in tax incentives, said Stephen Hearst, vice president of the corporation and great-grandson of William Randolph Hearst.

The price includes a conservation easement that puts more than 80,000 acres - an area twice the size of San Francisco - under a prohibition involving most development, said Sam Schuchat, executive officer for the California Coastal Conservancy.

The deal basically adheres to a proposal made in December 2002. If approved, it would be the largest conservation deal of its kind in state history, Schuchat said.

The conservancy is one of several state agencies that must sign off on the deal. Public hearings will be held this summer.

Funding will come from various bond measures already approved by California voters along with $23 million in federal transportation money.

Hearst attorney Roger Lyon said an independent appraiser has determined the land is worth more than double the asking price, but the company is willing to donate the difference.

Parties to the tentative agreement said they hope to finalize it by the end of the year.

"We couldn't be more pleased," Stephen Hearst said. "I think it's good for every stakeholder involved. … I think it's great for California, for the environment."

Under the tentative deal, the company would give up the option to develop as many as 400 homes but retained the right to build a total of 27 homes on separate five-acre sites not covered by the housing prohibition.

The homes wouldn't be visible from Hearst Castle or Highway 1. The corporation also could build a 100-room inn.

The Sierra Club, which has fought development of the ranch for decades, previously expressed concern about the proposal and was taking a wait-and-see attitude about the tentative deal.

"We know that the state has been negotiating hard to get the best deal for the public. We don't know what that deal is yet and we won't know until they hammer out all the details," said Tarren Collins, who chairs the local Sierra Club chapter.

Collins said her group wanted to be sure the conservation limits would be enforced and would be unchangeable. Another concern was whether the agreement would prohibit agricultural development.

Under current San Luis Obispo County law, the Hearst Corp. could build "wineries, dude ranches and slaughterhouses" without going through development hearings, she said. That raises concerns about water use, fencing and pesticides.

Lyon said the deal "will definitely detail restrictions on intensified agricultural uses." He declined to provide specifics but said they will be laid out before the public hearings.

Lyons said the intent is to preserve a "working landscape" that permits the area's historic cattle ranch while prohibiting extreme changes to the environment.

George Hearst bought the first acres of the ranch in 1865. His son, William Randolph Hearst, later built Hearst Castle and filled the huge complex with art. It is now a state historical monument that draws visitors from around the world.

The Hearst Corp. began looking into selling the land and development rights after the California Coastal Commission in 1998 shot down a proposal to build an 18-hole golf course and 650-room resort on some of the ranch property.

The region is considered among the most beautiful in California, boasting miles of coast teaming with sea otters and elephant seals as well as inland forests and grasslands that are home to zebras and other exotic species imported by William Randolph Hearst.

The ranch is home to threatened red-legged frogs, endangered steelhead trout, native poppies and several species of oak found nowhere else. There are 1,000 species of plants and animals on the ranch.

"Our hope is that the ranch stays pretty much like it is today forever," said Al Wright, executive director of the Wildlife Conservation Board, which also must approve the deal.

On the Net:

Hearst Castle: http://www.hearstcastle.org/

California Coastal Conservancy: http://www.coastalconservancy.ca.gov/

American Land Conservancy: http://www.alcnet.org/

Hearst Corp.: http://www.hearstcorp.com/