In 1953, U.S. Naval Security Group Department, NCS San Francisco, Skaggs Island, CA was established as a Dept of NAVCOMMSTA San Francisco.
NAVRADSTA San Francisco was disestablished, and was absorbed by the NSG Dept at Skaggs Island. On June 30, 1962, the NSG Dept stood down, and was reactivated on July 1, 1962 as the U.S. Naval Security Group Activity, Skaggs Island, Sonoma, CA. Also in 1962, NAVCOMSTA San Francisco moved from downtown San Francisco to Stockton, CA. Simultaneously, the Radio Receiving Station at Skaggs Island was re-established on July 1, 1962, and was renamed NAVRADSTA (R) Skaggs Island, CA.

Operating primarily as an HFDF (High Frequency Direction Finding) communications facility, Skaggs Island also hosted the MUSIC and STREAMLINER systems, and a TACINTEL Software Support Group. Its missions included electronic maintenance, communications relay, fleet broadcast support, ship/shore communications support, software support and training. NSGA Skaggs Island’s NFDF mission was unique. As Alternate Net Control Officer (ANCO) for both the Atlantic HFDF Net and the Pacific HFDF Net; Skaggs Island was called upon to take over either or both the Atlantic and/or Pacific HFDF Nets, usually on very short notice. The Tech Controllers at NSGA Skaggs Island often referred to that capability as ANCO World, in a mostly derogatory manner. It was not unusual for ANCO Skaggs Island to assume a scheduled HFDF Net Control shift, only to be told that the other HFDF Net had failed. It then became necessary to “Drop LANT and pick up PAC”, or vice versa.

HFDF communications aided in locating distant sources of communications by intercepting signals reflecting off the ionosphere.  Skaggs Island provided communication support to the Navy and other Department of Defense elements. The communications facility located on the island included an operations building located in the center of an AN/FRD-10A Circularly Disposed Antenna Array (CDAA) (A), also known as a Wullenweber antenna array. The CDAA ceased operations on June 18, 1993; and the CDAA was dismantled. The CDAA property is to be transferred to the U.S. Fish and Wildlife Service.

The U.S. Naval Security Group Activity, Skaggs Island, Sonoma, CA was closed and disestablished on June 18, 1993. The receiver site, NAVRADSTA (R) Skaggs Island, was also closed on that date.

For over 50 years, Skaggs Island was a secure self-contained Naval base. During that time, as many as 400 Navy personnel were stationed at Skaggs Island. Most of the buildings are residential and recreational buildings, including rows of single story homes, a theater, mess hall, recreation center, chapel, bachelor’s quarters, and administrative buildings, all of which are now abandoned and in a state of disrepair.

Besides the main base, and an unrelated aviation beacon, the only other structures of any size on the base are two block houses that contained transmitting and computer equipment. They are now abandoned and partially stripped of their contents. Recently, the walls of these buildings have been penetrated by Navy SEALs, practicing forced entry methods, and detonating explosives.

On March 31, 2011, Skaggs Island became part of the 13,000 acre San Pablo Bay National Wildlife Refuge created to protect migratory birds, wetland habitat and endangered species.


Skaggs Island was named for Marion Barton Skaggs, who financially helped the struggling Sonoma Land Company during the depression of the 1930s.

Skaggs Island is a drained area of San Pablo Bay tidelands approximately twenty-five miles northeast of San Francisco. The Navy developed the northern sixty acres of Skaggs Island as a self sufficient communications base. Skaggs Island was called an “island” because it was completely surrounded by narrow waterways called sloughs.

NSGA Skaggs Island was located in northeastern Sonoma county, about 10 miles north of Vallejo, CA (home of the Mare Island Naval Shipyard), and about 14 miles south of Novato, CA; on the northeastern shore of the San Francisco Bay. Skaggs Island was about 10 miles southwest of Napa, CA. Sonoma, CA is about 18 miles northeast of Skaggs Island. Two gates provide access to the base, one off Highway 37, and one from the north side. The main entrance is east of Sears Point, on Highway 37, on Skaggs Island Road, which leads in a straight line from the highway to the abandoned guard shack at the southern gate. Skaggs Island Road junctions with Highway 37, which leads to Vallejo to the south and Novato to the north. The north gate, which is situated next to a commercial farm, leads to Napa and Sonoma.

The history of Skaggs Island can be traced back to the days of the gold rush in 1849, when the island and parcels of land surrounding it were sold in small pieces as gold bearing property. In 1873, U.S. Senator John P. Jones of Nevada purchased the various parcels of land, which constituted what was later name Skaggs Island, and the surrounding area, and turned over the 10,000 acre plot to his brother for development.

At first, the land was used to raise draft horses. Later, a barley crop was planted with great success. However, to obtain any reasonable production from the acreage, land improvements had to be made, which took some 37 years to complete. Each of the six parcels of land involved in this program was referred to by its respective camp number. The #6 parcel, consisting of 4,390 acres, subsequently became known as Skaggs Island, and was the last parcel completed. The most important step in this development was the building of levees to hold back the sloughs, which laced the marshy land. Chinese coolie laborers, unemployed following the completion of the Central Pacific Railroad project, were used in the beginning, but ultimately, clamshell dredgers had to be brought in to finish the job in the 1920’s.

During the depression years of the 1930’s, the Sonoma Land Company, which had been organized during the development stage to handle business involving the land, encountered financial difficulties, and the company was forced to obtain the backing of Marion Barton “M. B.” Skaggs, a financial giant, and a member of an entrepreneurial family, who became a major retailing force, and the originators of what resulted in several well-known retail chains that carried not only the Skaggs name itself, but names like Safeway, Osco, PayLess, Albertsons, Longs Drug Stores, and others. It was this man for whom Camp #6, Skaggs Island, was named.

In 1940, the Navy was in search of a receiver site for San Francisco. Following various soil conductance tests, the choice was narrowed down to two locations, Grass Valley in the Sierra Foothills, just north of Sacremento, and Skaggs Island. Skaggs Island was ultimately selected because of its radio wave receiving characteristics and its location near the San Francisco headquarters.

In 1941, while the nation was preparing for war, the Navy purchased 3,300 acres of Skaggs Island from the Sonoma Land Company for $53 per acre, for the purpose of building a radio receiver site for the Naval Communications Station, to serve the San Francisco area. Construction began immediately on 13 sets of duplex houses and the OIC quarters, a 75-man barracks, a dispensary, a laundry, two operations buildings, a recreation hall and the gatehouse. The government paved an access road and strengthened the bridge across the slough at the north end of the island.

Shortly after 1941, the U.S. Navy established a Naval Radio Receiving Station (NAVRADSTA) (R) at the Skaggs Island facility. NAVRADSTA San Francisco was subordinate to the Naval Communications Station (NAVCOMMSTA) San Francisco.

NAVCOMMSTA San Francisco’s headquarters was located on the 4th floor of the Federal Office Building in San Francisco, until 1962, when it moved to Stockton, CA. There were three microwave links connecting the sites. One between San Francisco and Skaggs Island, one between San Francisco and Mare Island and one between Mare Island and Skaggs Island. There was an auxiliary transmitter station at Dixon, CA with approximately 10 HF transmitters. This site later became the main transmitter facility for NAVCOMMTSA San Francisco when the transmitter facility at Mare Island was shut down between 1962 and 1975.

On March 9, 1942, the Naval Security Group moved in at Skaggs Island, and COMSUPACT Skaggs Island, CA was established, and co-located at the NAVRADSTA.

In the early 1950’s, Building 43 was built to house the communication facilities.  These facilities were subsequently moved to Stockton. In later years, the signals received at the Receivers Building at Skaggs Island, were transmitted to NCS San Francisco on a microwave link via a microwave tower built on Mt. Diablo. The original communications facility, Building 43, ultimately became the NSGA Skaggs Island Administration building.

In the early years of the station, flooding of the antenna fields by the surrounding sloughs was a continual problem during the rainy season. In fact, the flooding caused part of the original antenna field to be built on barges. Improvements in land reclamation methods, including raising the levees, digging and enlarging approximately 30 miles of drainage ditches, and installing pumps capable of moving large quantities of water, made almost the entire 3,300 acres of the land arable. At any given time during the Navy’s ownership of Skaggs Island, as many as 2,900 acres of the station were being leased to private individuals for hay farming.

(A) Fielded by Federal Electric Co same as Winter Harbor, ME and Okinawa. The later AN/FRD-10A HFDF systems were fielded by Sylvania Co under the Bullseye program and included many new features.