- Historic California
Posts, Camps, Stations and Airfields
- Coast Guard Training Center, Petaluma
- (Two Rock Ranch Station)
The Training Center operates no less than 10 schools offering
50 courses to approximately 4000 students a year. In addition
to Coast Guard military and civilian employees, the Training
Center also provides training to international students. Located
in the rolling hills of the Two Rock Valley, this large training
command provides apprentice level training for seven enlisted
career fields and manages CG-wide training in leadership and
Total Quality Management for personnel at all levels of the organization.
The unit provides performance technology courses in basic instructor
skills and course designing skills. The Training Center also
provides courses for emergency medical technicians, maritime
law enforcement, and computer operation and management. The Training
Center consists of over 800 acres with 219 buildings, including
129 family units, a fully staffed clinic, a chapel, a small police
and fire department, and over 200,000 square feet of training
- In 1942, the Army purchased Two Rock Ranch
and built a Communications Station. The station's location was
ideal for monitoring Japanese communications during World War
II. Operations at the station were top-secret.
- During the Vietnam War, the station added
training to it's mission. Portions of the base were transformed
into a Vietnamese village to train troops headed for Vietnam.
In the late 1960's, satellites and other technological advances
made the listening post obsolete and preparations were made to
close the base.
- With the Vietnam War in progress, the
Coast Guard faced increased training demands. The Training Center
at Governor's Island in New York became overcrowded, so the Coast
Guard started looking for a suitable site for a new training
center. In the spring of 1971, The Coast Guard learned of the
closing of Two Rock Ranch Station. Officials visited the property
and were impressed with the station. Although the California
Highway Patrol and an Indian group were interested in the land,
the Coast Guard was awarded the station. On July 1, the Coast
Guard relieved the Army and took possession of the station.
- Soon after taking over the property, it
was decided that the name "Two Rock Ranch" was not
suitable for a Coast Guard Base. In spite of interest in retaining
"Two Rock" as part of the new name, the base was renamed
Coast Guard Training Center, Petaluma. Interestingly, one reason
Petaluma was chosen over Two Rock was that Petaluma appeared
on many maps whereas Two Rock did not. This was considered important
for Coast Guard members who would be trying to locate the base
when traveling to it.
- Immediately after the training center
opened, Subsistence Specialist school began training Coast Guard
cooks. Soon after that, Storekeeper school opened. Approximately
6 months later the Radioman School opened. In April of 1972,
less than a year after it opened, the base was fully loaded with
- The nearest town to the Training Center
is Petaluma, the second largest and southernmost city of Sonoma
County. Started as a riverbank hunting camp in the 1850's, Petaluma
quickly grew into an agricultural, trade and industrial hub that
by 1918 claimed the title of "Egg Basket of the World".
Petaluma was the richest city of it's size in the United States
during the 1920's partly because of the cheap transportation
for agricultural products offered by the Petaluma River. Today
Petaluma still retains some of it's agricultural flavor, but
it is becoming a nice bedroom community of the Bay area job market.
Downtown has been renovated and cafe's abound for the weekend
antique shoppers who flock to the wide assortment of shops. Housing
in Petaluma is a mixture. Newer homes on the east side of Hwy
101 and older ones on the west. Filmmakers especially like the
older, well kept west side for it's quaint, all-American looks.
The city has had parts in movies since the 1940s, including "Basic
Instinct","Peggy Sue Got Married", and "American
- Copied with permission from
Army Corps of Engineers Chronological Site Summary for Two Rock
On 7 August 1942,
Two Rock Ranch Station was established as a primary monitoring
station under the command of the Chief Signal Officer. The area
had been dairy and poultry farms prior to War Department purchase
of the nine tracts. The first contingent of troops to occupy
the installation included two (2) officers and 45 enlisted men
from Fort Monmouth, New Jersey, who arrived in October 1942.
The only billeting consisted of tents while the former ranch
houses were converted for use as administrative and operational
The primary mission of Two Rock Ranch Station was the interception
of enemy radio transmissions with a secondary mission of training
radio operators for service in the Pacific Theater. By 9 April
1943, 23 buildings had been constructed and the number of personnel
assigned had been increased from 200 to 521 men. All buildings
were camouflaged to give the appearance from the air that the
installation was nothing more than a working ranch. A haystack
covered the water tower, furrows were plowed and planted, and
an artificial cow made of feathers over a wire frame was placed
in a pen.
In October of 1943, a contingent of approximately 100 Women's
Army Corps (WAC) personnel was assigned as radio operators. These
personnel stayed until the end of the war.
At the end of World War II, Two Rock Ranch Station was redesignated
as a special installation under the command of the Army Security
Agency (ASA). The mission of monitoring radio transmissions for
intelligence purposes remained the same. An ambitious program
of modernization was begun wherein most of the original ranch
buildings and World War II structures were replaced by more modern,
On 25 April 1947, a tract containing 35.37 acres was transferred
from the War Department to the War Assets Administration (WAA)
. An additional 5.36 acres was quitclaimed to the Two Rock Union
School District on 11 December 1951.
Advances in satellite technology eventually made the antenna
fields at Two Rock Ranch Station obsolete and the installation
was closed on 30 June 1971. On 29 July 1971, the Department of
the Army transferred the remaining 835.68 acres to the U.S. Coast
Guard (USCG), Department of Transportation (DOT) for use as a
USCG training center. The USCG also obtained the 35.37-acre tract
that had been transferred to the WAA in 1947.
In 1985, DOT conveyed two parcels consisting of 30.89 acres and
35.37 acres to private individuals. An additional 8.56-acre tract
was deeded to the Two Rock Union School District.
- Historic Military
Due to the nature of the site, a radio receiving station, and
the highly classified nature of the work performed, the use of
military munitions on the site was extremely limited. During
World War I1 those individuals assigned guard duty were issued
small arms. These consisted of .45 caliber submachine guns and
12-guage shotguns. Ammunition and weapons were stored and issued
at the guardhouse. There were no ranges during this period.
Sometime prior to 1952, two ranges consisting of a double skeet
range and a 1,000-inch small arms range were constructed. The
double skeet range is still in use by the U.S. Coast Guard. The
small arms range was recreational in nature and was also used
with M1 carbines by Boy Scouts. This range continued in use until
at least 1961. Qualification for record was not performed at
Two Rock Ranch Station but at other military facilities in the
San Francisco Bay area.
Two magazines, buildings 539 and 540, were constructed in 1968.
These were identified as ready magazine and a fixed ammunition
magazine. These two magazines were used to store shotgun ammunition
for the skeet range. Although the U.S. Coast Guard did not use
these magazines, they continued to exist at least until 1984.
An indoor pistol range was built in 1965. This range was identified
as Building T831. The U.S. Coast Guard demolished this building
in 1997 and the bullet trap was environmentally mitigated. No
further action is contemplated for this site.
A mock 'Vietnam Village' was constructed of local materials in
the late 1960s. This mock village was used in a training course
for ASA personnel in dealing with the conditions in Vietnam.
According to several eyewitness accounts, only blank small arms
ammunition was used in these activities.
- Source: Archives
Search Report, US Army Corps of Engineers, Rock Island District,
from Historical Data Cards, US Army Center of Military History
- Two Rock Ranch
- The Primary Monitoring
Station under construction at Two Rock , Petaluma, California,
is classified as an installation under the command of the Chief
Signal Officer in accordance with the provisions of para. 6 a
(4)(a) AR 170-10, SPX (7-24-42)MR-M-P. dated August 7 , 1942
Two Rack Ranch Station is a subordinate agency of the Signal
Security Agency, Washington, D.C., per 1st OCSigO dated 25 Aug
44, SPSEC 321 Sig C Org (19 Aug 44) (C).
Two Rocks Ranch Station, Petaluma, California, is reclassified,,
effective 15 Sept. 1945, as a special installation under the
control of the Chief, Army Security Agency, in accordance with
AR 170-10, para 63(5), pursuant to authority contained in AG
322 (4 Sep 45) OB-S-B-M, dated 6 Sept. 1945. per AG. 323.3 (17
Sep 45) OB-S-B, dated 21 Sept. 1945. Any previous instruction:
in conflict with the foregoing are superseded.
Effective 12 June 1946, the Two Rock Ranch Station. Petaluma,
Calif. is reclassified as a class II activity and under the jurisdiction
and control of the Director of Intelligence in accordance with
WD Cir. # 135, 1946 - per WD Cir. # 169 dated 11 June 1946. Rescinded.
Eff 9-25-46 reclass II install under Dir./Intell in accord/WD
Cir.138,46-per WD Cir. #292, dtd,9-25-46.
Two Rock Ranch Station; ,Petaluma, Calif., a Class II installation,
is hereby classified as "SECRET" - per AG 680.1 (6
Sep 46)A0-1-WDGID-M, dated 12 September 1946. RESCINDED: AGAO-I
- Photographic Laboratory,
Two Rock Ranch Station, Petaluma, California shown on list of
photograhic laboratories as a class II installation under the
jurisdiction of the Director of Intelligence, WDGS - per Ltr.,
Hq Sixth Army, Presidio of San Francisco, California, 6 November
ASU, Two Rock Ranch, Petaluma, Calif. reorganized under T/D #206-1900
dated 1 Oct 47 - per Sixth Army T/D for person: authorized in
ASU #6900, Two Rock Ranch. Petaluma, Calif. is reorganized under
T/D #206-1900, Hq Sixth Army, 30 June 1948.
6900 ASU, Sv Det, Two Rock Ranch, Petaluma, Calif. to be reorgnd
under T/D #206-1900, Hq Sixth Army, 30 June 49 & 31 Dec 49,
Effective 1 July 1950, the Dispensary, Two Rock Ranch is redesignated
the US Army Dispensary, Two Rock Ranch with location Petaluma,
California per GO 21, Dept of the Army, 6 July 1950
- 8602d Administrative
Area Unit, Field Station is organized at Two Rock Ranch Station,
Petaluma, California, effective 15 May 1950 - per Copy of GO
13, Hq Army Security Agency, 12 May 1950. See also GO 5, Hq Two
Rock Ranch Station, Petaluma, California, 15 May 1950.
- Is designated a permanent
DA installation effective 1 July 1954 - GO 60, DA, 16 Aug 1954
- Two Rock Ranch Station,
Calif, a Class II installation, ASSIGNED to Army Security Agency
is REDESIGNATED as a class III installation effective 1 July
1955 - GO 23, DA, 25 Mar 1955.
- Two Rock Ranch Station,
Calif, a Class III installation, ASSIGNED to Army Security Agency
is REDESIGNATED as a class II installation - GO 35, DA, 25 Jul
- TD 66-6350-00 is ASSIGNED
to US Army Dispensary, Two Rock Ranch Station at Petaluma, Calif
effective 1 Jan 1959 - GO 203, Sixth US Army, 29 Dec 1958.
- TD 93-8602 is WITHDRAWN
and TD 86-9319 is ASSIGNED effective 1 Mar 1959 - Ltr, GAS23
250/29(17), US Army Security Agency, Arlington Hall Station,
2 Feb 1959.
- Two Rock Ranch Station,
California is to be DISCONTINUED effective 30 Jun 1971 - DCSLOG
ltr 21 Jun 1971.
- Two Rock Ranch Station,
California is DISCONTINUED effective 30 Jun 1971 - GO 86, USASA,
26 Apr 1971.
- Effective 30 June 1971,
Two Rock Ranch Station, California, a class II installation under
the jurisdiction oftheCommanding General, US Army Security Agency,
is placed in an inactive status - GO 29, HQDA, 24 June 1971
- US Army Garrison,
Two Rock Ranch Station
- US Army Garrison, Two
Rock Ranch Station is ORGANIZED at Two Rock Ranch Station, Petaluma,
Calif as a separate class II activity, ASSIGNED TD 86-9319-O2,
1961 with an authorized strength of 6 OFF, 88 ENL,, 46 CIV, ASSIGN]
to 2d US Army Security Agency Field Station, Two Rock Ranch Station,
Petaluma, Calif effective 1 Jul. 1961 - GO 32, US Army Security
Agency, 15 Jun 1961.
US Army Garrison, Two Rock Ranch Station is DISCONTINUED effective
1 May 62 - GO 23, US Army Security Agency, 13 Apr 62.
- Additional Online Information
- US Army
Corps of Engineers Rock Island District Archive Search Report
Posted 18 February 2010