: 1 meter = 3.28 feet; 1 meter =
1.09 yards; and 1 kilometer = 0.62 miles. Vertical distances are
given in feet; altitudes are measured from mean sea level, while
heights are measured from surface level, unless otherwise noted.

Ground zero for the TRINITY detonation was at UTM coordinates
630266.** Three shelters, located approximately 9,150 meters (10,000
yards) north, west, and south of ground zero, were built for the
protection of test personnel and instruments. The shelters had walls
of reinforced concrete and were buried under a few feet of earth. The
south shelter was the Control Point for the test (12). The Base Camp,
which was the headquarters for Project TRINITY, was located
approximately 16 kilometers southwest of ground zero. The principal
buildings of the abandoned McDonald Ranch, where the active parts of
the TRINITY device were assembled, stood 3,660 meters southeast of
ground zero. Seven guard posts, which were simply small tents or
parked trucks like the ones shown in figures 1-3 and 1-4, dotted the
test site (9).

** Universal Transverse Mercator (UTM) coordinates are used in this
report. The first three digits refer to a point on an east- west
axis, and the second three digits refer to a point on a north-south
axis. The point so designated is the southwest corner of an area 100
meters square.

1.3 THE PROJECT TRINITY ORGANIZATION

The organization that planned and conducted Project TRINITY grew out
of the X-2 Group. LASL, though administered by the University of
California, was part of the Manhattan Project, supervised by the Army
Corps of Engineers Manhattan Engineer District. The chief of MED was
Maj. Gen. Leslie Groves of the Army Corps of Engineers. Major General
Groves reported to both the Chief of Engineers and the Army Chief of
Staff. The Army Chief of Staff reported to the Secretary of War, a
Cabinet officer directly responsible to the President. Figure 1-5
outlines the organization of Project TRINITY.

The director of the Project TRINITY organization was Dr. Kenneth
Bainbridge. Dr. Bainbridge reported to Dr. J. Robert Oppenheimer, the
director of LASL. A team of nine research consultants advised Dr.
Bainbridge on scientific and technical matters (3).

The Project TRINITY organization was divided into the following
groups (3):

o The TRINITY Assembly Group, responsible for assembling and arming
the nuclear device

o The TR-1 (Services) Group, responsible fo