History

History of the land

• The Coast Miwok: In 1769, during their first contact with Europeans, the Coast Miwok population numbered roughly 1,500, and their hunting grounds spanned all of Sonoma Mountain. By 1930, their numbers had declined to approximately 500.

• Rancho Petaluma (1834–1857): The southern slope of Sonoma Mountain, from the Petaluma River to Sonoma Creek, was originally part of Rancho Petaluma. Granted to General Mariano Vallejo in 1834 at 44,000 acres, the rancho was later extended to more than 66,000 acres, stretching from San Francisco Bay to Glen Ellen. Vallejo sold the Petaluma Adobe and its surrounding land in 1857. By the time the Rowe survey was recorded in 1866, the acreage had been fractured into numerous parcels—some sold by Vallejo, others claimed by Anglo squatters.

Early development of Diamond A

In 1961, Berrien Anderson sold the ranch to developers Thomas Burke and Jack Fisher for $400,000. (Fisher lived in Unit #1 at 3775 Burke Place until his death on March 12, 2003).

The initial vision for the "Diamond A Ranch Estates" was expansive. A 1965 preliminary master plan proposed dividing 1,220 acres into 482 home sites (1.5 to 2.5 acres each), alongside extensive recreation areas near Carriger Creek and the steep, wooded slopes. While the master plan mapped out Units 1 through 5, the full 482-lot density was never realized; 290 of those planned lots were ultimately consolidated into larger parcels.

The First Phases

Early milestones moved forward under exclusive realtor Robert "Bob" Garlick, who managed sales out of the old ranch house:

• Unit 1 & Unit 2: Recorded in 1962 under Kenleigh Homes Incorporated by T.E. Burke, establishing 25 and 28 lots respectively.

• Infrastructure: According to Garlick's son, Dave, plans originally called for a multi-phase development of 500 to 600 lots ranging from 1.5 to 3 acres. Phase one replaced a winding, 20-minute, single-lane road with a steep, straight approach from the old Van Hoosear Ranch.

• The sales boom: The first two phases went well, with lots selling for $6,000 to $8,000 each. Bay Area residents were drawn to the magnificent views, abundant Live Oak, White Oak, and Pepperwood, and fields that turned purple and orange each spring with lupine and poppies.

The remaining property later changed hands when two marketing-savvy Stanford graduates bought out Fisher and Burke. They launched aggressive promotions, running San Francisco radio ads and touring prospective buyers in a "Rolls Royce Jeep" driven by "Trail Boss" Bob Garlick. Phase three began with strong momentum.

A change of direction: landslide and foreclosure

Disaster struck in the late 1960s when a lot owner below the old ranch house undertook significant grading without permits. The ensuing winter rains triggered a major landslide, severely damaging the road below.

Sonoma County immediately issued a building moratorium pending geologic and landslide studies. The final county report categorized the risk across the remaining development:

• High Risk: 27 lots

• Intermediate Risk: 95 lots

• Low Risk: 65 lots

As a result, the county tightened foundation requirements. This regulatory process took a couple of years, and the resulting delays forced the developers into foreclosure.

During these bleak years, the developers tried to sell the remaining acres in a single block. A prospective buyer proposed building a world-class golf course, but during a site visit, "Trail Boss" Bob parked his Jeep at the highest point of the ranch, and the stick shift was accidentally knocked into neutral. Both men watched the Jeep roll down the hill and crash into an oak tree. Following a grueling two-hour walk out, the golf course plans were abandoned.

The remaining acreage was ultimately sold to the highest bidder on the courthouse steps, shifting future development toward much larger lots ranging from 10 to 40 acres.

Final subdivision evolution

Official filings tracking the remainder of the development included:

• Unit 3 (Feb 18, 1965): 56 lots filed by Fisher and Burke, Inc. (T.E. Burke, Pres.; Jack Fisher, Sec./Treas.)

• Unit 4 (Oct 29, 1965): 4 lots filed by William J. Troy (Sonoma Land Corporation)

• Unit 5 (Dec 29, 1966): 71 lots filed by William J. Troy (Sonoma Development Corporation)

• Diamond A Ranches (Dec 23, 1976): 16 lots in the northeast sector filed by the Piombo Corporation

Ultimately, the old Anderson Ranch split into two distinct subdivisions: The Diamond A Ranch Estates and The Diamond A Ranches. Over time, leftover pieces were further subdivided and developed. The final layout stabilized at 240 total lots—roughly half of the density proposed in the 1965 master plan. Several lots have been built upon since 1999. A 2007 telephone directory recorded 199 households, reflecting that some lots contain multiple households.

Future development

This history reveals that comprehensive county oversight only arrived after nature intervened. The late-1960s landslide effectively halted over-development, sparing the eastern flank of Sonoma Mountain from much denser housing.

Could a massive subdivision like Diamond A happen again today? Probably not. In 1998, Sonoma Mountain Preservation helped enact strict development guidelines, which are now closely monitored by both Sonoma County and Sonoma Mountain Preservation.

Photo Gallery

The photo gallery below shows some of the activity at the Diamond A Ranch in the 1950's and a recent picture of the Diamond A "brand". These photos were taken before any development took place, and show that Diamond A was a working ranch. 

References

The research for this article was done by John Barinaga, Marilyn Goode, Beverly Perrin, and Jack Nisson.  They used the following sources:

• Sonoma Mountain Preservation Diamond A page

• Sonoma Mountain Preservation Sonoma mountain history page

• Coast Miwok Wikipedia page

• California State Parks Petaluma Adobe State Historic Park history page

• Illustrated atlas of Sonoma County, 1898, Reynolds & Proctor, Santa Rosa

• An illustrated history of Sonoma County, California, 1889, The Lewis Publishing Company, Chicago

• History of Sonoma County, California, 1911, Thomas Jefferson Gregory, Historic Record Company, Los Angeles

• The Sonoma Index-Tribune

• Diamond A Property Owners' Association

• Property transfer dates sourced from the Sonoma County Assessor’s Office