  Magnetic fields permeate the interstellar medium and are important in the
star formation process. Determining the 3D magnetic fields of molecular clouds
will allow us to better understand their role in the evolution of these clouds
and formation of stars. We fully reconstruct the approximate three-dimensional
(3D) magnetic field morphology of the Orion A molecular cloud (on scales of a
few to ~100 pc) using Galactic magnetic field models, as well as present
line-of-sight and plane-of-sky magnetic field observations. While previous
studies identified the 3D magnetic field morphology of the Orion A cloud as an
arc shape, in this study we provide the orientation of this arc-shaped field
and its plane-of-sky direction, for the first time. We find that this 3D field
is a tilted, semi-convex (from our point of view) structure and mostly points
in the direction of decreasing latitude and longitude on the plane of the sky,
from our vantage point. The previously identified bubbles and events in this
region were key in shaping this arc-shaped magnetic field morphology.
