The Sonoma Land Trust and the Sonoma County Agricultural Preservation and Open Space District will buy the land by the end of the year.
The purchase will mark the completion of a long-awaited public access trail across the top of Sonoma Mountain, the signature mountain in the county that serves as a backdrop for the Sonoma Valley, Petaluma Valley and Santa Rosa.
Wendy Elliot, Sonoma Land Trust's conservation director, said, "The public should have access to every peak ringing San Francisco Bay. People can hike to the tops of Mount Tamalpais, Mount St. Helena, Mount Diablo and San Bruno Mountain, and now they'll be able to hike to the top of Sonoma Mountain too."
The latest parkland acquisition sits at an elevation of 2,463 feet and it offers views of the Pacific Ocean, San Francisco Bay and on clear days, the Sierra Nevada Mountains.
Jack London State Historic Park lies to the east and the Osborn Preserve is to the west of the new park.
"We are fortunate to have the opportunity to purchase this significant property and create an unbroken band of 5,500 acres of publicly protected land on Sonoma Mountain," said Supervisor Valerie Brown, whose district includes the property.
The land, also known as the Walsh Property, was owned by the Stevenson family. It became available for purchase in September.
The Sonoma Land Trust anticipates receiving a $1.5 million grant from the State Coastal Conservancy to assist with the purchase. Escrow on the property is to close by Dec. 31. The open space district will contribute $8,450,000.
The property contains oak woodlands, grasslands, wetlands and headwaters of stream corridors that are home to steelhead.
Communication towers used by PG&E, AT&T and emergency service providers are also located on the property.