  The Fermi Large Area Telescope (LAT) has amassed a large data set of primary
cosmic-ray protons throughout its mission. The LAT's wide field of view and
full-sky survey capabilities make it an excellent instrument for studying
cosmic-ray anisotropy. As a space-based survey instrument, the LAT is sensitive
to anisotropy in both right ascension and declination, while ground-based
observations only measure the anisotropy in right ascension. We present the
results of the first ever proton anisotropy search using Fermi LAT. The data
set uses eight years of data and consists of approximately 179 million protons
above 78 GeV, enabling it to probe dipole anisotropy below an amplitude of
$10^{-3}$, resulting in the most stringent limits on the declination dependence
of the dipole to date. We measure a dipole amplitude $\delta = 3.9\pm1.5 \times
10^{-4}$ with a p-value of 0.01 (pre-trials) for protons with a minimum energy
of 78 GeV. We discuss various systematic effects that could give rise to a
dipole excess and calculate upper limits on the dipole amplitude as a function
of minimum energy. The 95% CL upper limit on the dipole amplitude is
$\delta_{UL}=1.3\times 10^{-3}$ for protons with a minimum energy of 78 GeV and
$\delta_{UL}=1.2 \times 10^{-3}$ for protons with a minimum energy of 251 GeV.
