Marconi State Historic Park has a rich human history that dates back hundreds of years. The Tomales Bay ecosystem has supported the livelihoods of people—from the pre-historic villages of the Coastal Miwok to the farming communities of today. Amazingly, Tomales Bay has maintained is pristine waters and rural charms.

Marconi lies in the ethnographic territory of the Coastal Miwok.  In the latter part of the 18th century, this tribe occupied most of Marin and part of Sonoma county. Their population was estimated, by early explorers, to be between 1,500 to 2,000 members.  The remains of several villages, scattered along the shores of Tomales Bay, attest to the abundance of natural resources that the bay afforded. The pre-historic tribal village of “ec-a kulum” is located just south of the current community of Marshall. Until the early 1800’s the Miwok were effective in preventing Spanish and Russian settlement of the Marin Peninsula.




In 1894, across the Atlantic in Bologna, Italy, a young man by the name of Guglielmo Marconi began experimenting with Electromagnetic Waves (Radio Waves).  In an unused portion of his parents' attic, Marconi constructed devices for sending and receiving Morse code across the room without the use of wires.  Through trial and error he steadily improved the distances he was able to send a signal, and soon outgrew his attic laboratory.

Within a year, Marconi was able to transmit a telegraph signal a distance of two miles.  By 1897, he had increased the distance to 15 miles, proving that man-made and natural obstacles did not interfere with the transmission of radio waves. Professor Hugh Aitken succinctly describes Marconi’s pivotal achievement in the development of radio:  “...he was at the culmination of the process whereby a major scientific advance was translated into practical use. Scientific theorem had already been translated into apparatus ... [which] could be used for tests



In 1817, the growing Russian presence to the north and the desire to recruit new converts motivated the Franciscans to move across the San Francisco Bay and establish Mission San Rafael. The land claimed by the friars included most of the Marin peninsula with the exception of Point Reyes. General Mariano Vallejo also established a fort in the North Bay and provided the military authority for the Spanish frontier.  With the secularization of the missions in 1835, the converted Miwok were granted a large inland tract of land known as Rancho Nicasio.  The land grant extended westward to include the eastern edge of Tomales Bay. Two years later, Vallejo concluded that the natives were “...not as a rule, making good use of their liberty...” and collected their land, promising to redistribute it when circumstances were more favorable.  By 1843, such favorable circumstances having failed to materialize, Governor Micheitoreno divided the natives’ grant among Mexican and Anglo claimants. Ten leagues of land (7,598 acres) along Tomales Bay, including the land now occupied by Marconi, were granted to William Reynolds and Daniel Frink, early California settlers.

and demonstrations...Marconi carried it one step further. He translated laboratory hardware into a technological system that could serve practical needs.” In Aitken’s view, although many of Marconi’s contemporaries were experimenting with the waves discovered by physicist Heinrich Hertz, Marconi’s genius was in foreseeing the practical potential of radio transmission.

In 1896, Marconi returned to his mother’s native England, and established the Wireless Telegraphic and Signaling Company of England.  His company provided Ship-to-Ship and Ship-to-Shore Wireless Telegraphy, the principal application of Marconi’s wireless, which was immediately recognized as significantly increasing the safety of marine transportation.

Marconi’s successes were rapid.  In 1899, he successfully transmitted radio waves across the English Channel.  In the same year, he was granted the English patent number 7777, the first radio patent ever issued.  Marconi then sailed to the United States and used a ship-based wireless transmitter to report on the America’s Cup race.  Soon after his arrival in the US, he established the Marconi Wireless Telegraph Company of America and pursued two major goals.  His first goal, a commercial radio empire, was achieved through a series of successful patent lawsuits against his competitors.  As a result, the Marconi Company emerged as the dominant player in this new field of Radiotelegraphy.

Marconi’s second goal was to push the boundary of accepted scientific theory and transmit radio signals across the Atlantic.  From his bases in Cape Cod and Cornwall, Marconi labored to span the Atlantic.  He succeeded in 1901 by moving his receiving base to Newfoundland and using a kite-supported antenna.  Over the next several years, Marconi endeavored to not only improve reliability and continuity of this signal, but also to increase transmission distances even further.  By 1907, the Americas and Europe were in regular commercial communication. The success of his transoceanic experiments led to the American and British companies' ambitious plan to establish a worldwide, high-power communications system.  These high-power stations would girdle the world and provide virtually instantaneous communications to every point on the globe.  In 1909, Marconi was awarded the Noble Prize for Physics adding to his already substantial fame.  Three years later Marconi would be credited with saving the 712 survivors of the Titanic disaster.

In 1912, a lawsuit against United Wireless resulted in the merger of the two companies.  Among the assets acquired by Marconi were 70 land stations and more then 500 ship-board installations. One of these stations was Station KPH, San Francisco’s first radio station.  In 1913, a new site was purchased and construction begun for the station’s new home.

The Marshall Receiving Station

In order to achieve a signal powerful enough to cross the Pacific Ocean, a new, more powerful station was built on the Marin Coast. This station was designed and constructed by J.G. White, a New York engineering firm. All Marconi’s transoceanic stations were “duplex” stations, geographically separated complexes for transmitting and receiving. The geographic separation was necessary because the noise of transmission obstructed clear reception. All these stations were nearly identical in construction. The imposing, two-story staff and visitors’ hotel with its wide veranda is the centerpiece of the receiving station. In addition to its thirty-five rooms - ten complete with private baths - the hotel boasted such comforts as a library, game room, lounge, and dining hall. Flanking the hotel to the left are two single-story bungalows for the chief and assistant engineers. To the right lies the powerhouse that contained the boiler, transformers, storage batteries and a workshop. The operations building, located a short distance from the bungalows, housed the receiving and printing equipment as well as the station’s administrative offices.

All the buildings are similar in architectural style, which might be described as Mediterranean Revival with Craftsman allusions. The steel, concrete, and tile materials were selected to ensure “... minimum charge for maintenance” and “maximum fire protection.” The Mediterranean stylistic elements include the extensive use of tile, the verandas, the symmetrical treatment of the fenestration, and the formal approach to the hotel. The Craftsman style, popular at the time of construction, can be seen in the decorative treatment of the eaves, the use of dormers (unusual in Mediterranean buildings), and employment of multi-panel upper sash windows. The Craftsman influence predominates in the interior of the hotel, with its restrained, rectilinear millwork, natural wood finishes and five cross-panel doors with transoms. Notable are the two massive first floor masonry fireplaces with their rustic half-log mantels. Early interior photographs show the rooms furnished with Craftsman furniture and ornamentation.

In addition to the permanent buildings, the American Marconi Company constructed several small wooden cottages. These served as housing for married employees and their families. On the hills above the operations building, stood the 270-foot towers that held aloft the mile-long antenna. Guide wires attached to four concrete anchors supported the masts.

World War I & The RCA Takeover

During World War I, the United States Government appropriated control of this technology.  The Marconi Company, deprived of its commercial wireless operations, pursued lucrative contracts to provide the Navy with new and upgraded submarine and shipboard transmitters.

After the war, the Marshall/Bolinas Station was returned to the Marconi Company and again became Station KPH. The experience of the war and the recognition of the strategic importance of radio communication led to subsequent government actions to secure control over radio communication.  Accordingly, in 1920, the Radio Corporation of America (RCA) was formed which bought the holdings of the American Marconi Company.  At the time, RCA was headed by a number of former Marconi officials, notably General David Sarnoff, who began his career in the mailroom of the Marconi Company.  RCA soon sold the majority of undeveloped land at the Marshall site, retaining only 62.7 acres surrounding the station buildings.

Although Marconi’s dream of heading a worldwide communication empire was over, he none-the-less continued experimenting with improving radio communications.  In 1923, he developed a short-wave beam system.  This system could not only be used for better long distance communication, but also for guiding ships safely into port even in dense fog.  With the implementation of short-wave signals, the operation at Marshall, which was a long-wave station, was relocated across Tomales Bay to the Point Reyes Peninsula for superior short wave reception.  RCA records indicate that while international radio communications ceased at the Marshall Station at that time, maritime service continued until 1939.




RCA continued to hold title to the Marshall site until 1947.  In the ensuing years, the property changed hands several times before it was acquired by the Synanon Foundation, then a Santa Monica based drug rehabilitation organization. Shortly afterward, the Marconi property became the “world headquarters” of Synanon, which also acquired other nearby ranch properties.

In the late 1960’s, Synanon began to de-emphasize its rehabilitation programs, and became a self-declared “alternative lifestyle community.” At its height, it had about 1700 members, a large number of whom lived at the Marshall property. In 1975, Synanon underwent another transformation, declaring itself a “church” and amassing a large cache of weapons. In 1979, a series of Pulitzer Prize-winning articles by the local newspaper, The Point Reyes Light, began to expose Synanon’s finances, internal practices and abuses in the local community. The state of California launched a special investigation into Synanon’s affairs and in 1980 Charles Dedrich, long-time leader of the organization, was convicted of conspiracy to commit murder.  As one of the largest, longest-lived, and certainly the most economically successful group of its kind, it should be recognized that Synanon will be the subject of scholarly interest and research. 

During Synanon’s occupation of the property, several buildings were constructed, as well as a variety of landscape elements added.  The buildings include a series of contemporary coastal shed-style residences and several corrugated metal structures scattered about the property.   The pond next to the tennis courts and the vegetation planted close to the hotel and other buildings are the most notable of the landscape elements added.




The antennas at the Bolinas Transmitting Station are silent; their last commercial message was sent in 1997.  The Marshall Receiving Station, last used as a radio station in 1939, was purchased by the San Francisco Foundation from Synanon in 1980 with the help of the Buck Trust. Four years later they transferred the property to the California State Parks Foundation, which in turn gifted the property to the State of California as a conference center in 1989.  The Marconi Conference Center opened its doors in January of 1990. 

Today this historic State Park is a place where communications of a difference sort echo thought through the halls of the grand buildings.   Marconi continues in the tradition of communication by providing meeting and retreat services for the Bay Area.

For the past few decades, Marconi State Historic Park & Conference Center has been dedicated to facilitating conferences in a rural setting. Just 50 miles north of San Francisco, Marconi is a great setting for trainings, leadership forums, team building, and endless inspiration.

More recently Marconi has opened its 62-acre park trails for day-use and its lodging for individual leisure overnight stays.

To view the CA State Marconi Conference Center & State Historic Park General Plan, go here.

To view the Dornbusch Marconi report, go here.

We want to recognize the Marconi Company Limited, England, for their help in compiling this history and for providing many of the historical photos you see in the History Photo Gallery.

Marine Radio Historical Society International Marconi Day - Centennial Celebration - click here for more information

Visit Maritime Radio Historical Society website