  We present an overview of the first data release (DR1) and first-look science
from the Green Bank Ammonia Survey (GAS). GAS is a Large Program at the Green
Bank Telescope to map all Gould Belt star-forming regions with $A_V \gtrsim 7$
mag visible from the northern hemisphere in emission from NH$_3$ and other key
molecular tracers. This first release includes the data for four regions in
Gould Belt clouds: B18 in Taurus, NGC 1333 in Perseus, L1688 in Ophiuchus, and
Orion A North in Orion. We compare the NH$_3$ emission to dust continuum
emission from Herschel, and find that the two tracers correspond closely.
NH$_3$ is present in over 60\% of lines-of-sight with $A_V \gtrsim 7$ mag in
three of the four DR1 regions, in agreement with expectations from previous
observations. The sole exception is B18, where NH$_3$ is detected toward ~ 40\%
of lines-of-sight with $A_V \gtrsim 7$ mag. Moreover, we find that the NH$_3$
emission is generally extended beyond the typical 0.1 pc length scales of dense
cores. We produce maps of the gas kinematics, temperature, and NH$_3$ column
densities through forward modeling of the hyperfine structure of the NH$_3$
(1,1) and (2,2) lines. We show that the NH$_3$ velocity dispersion,
${\sigma}_v$, and gas kinetic temperature, $T_K$, vary systematically between
the regions included in this release, with an increase in both the mean value
and spread of ${\sigma}_v$ and $T_K$ with increasing star formation activity.
The data presented in this paper are publicly available.
