  We present the third MAXI/GSC catalog in the high Galactic-latitude sky ($|b|
> 10^\circ$) based on the 7-year data from 2009 August 13 to 2016 July 31,
complementary to that in the low Galactic-latitude sky ($|b| < 10^\circ$; Hori
et al. 2018). We compile 682 sources detected at significances of $s_{\rm
D,4-10~keV} \geq 6.5$ in the 4--10 keV band. A two-dimensional image fit based
on the Poisson likelihood algorithm ($C$-statistics) is adopted for the
detections and constraints on their fluxes and positions. The 4--10 keV
sensitivity reaches $\approx 0.48$ mCrab, or $\approx 5.9 \times 10^{-12}$ erg
cm$^{-2}$ s$^{-1}$, over the half of the survey area. Compared with the
37-month catalog (Hiroi et al. 2013), which adopted a threshold of $s_{\rm
D,4-10~keV} \geq 7$, the source number increases by a factor of $\sim$1.4. The
fluxes in the 3--4 keV and 10--20 keV bands are further estimated, and hardness
ratios (HRs) are calculated using the 3--4 keV, 4--10 keV, 3--10 keV, and
10--20 keV band fluxes. We also make the 4--10 keV lightcurves in one year bins
for all the sources and characterize their variabilities with an index based on
a likelihood function and the excess variance. Possible counterparts are found
from five major X-ray survey catalogs by Swift, Uhuru, RXTE, XMM-Newton, and
ROSAT, and an X-ray galaxy-cluster catalog (MCXC). Our catalog provides the
fluxes, positions, detection significances, HRs, one-year bin lightcurves,
variability indices, and counterpart candidates.
