  We present quantitative statistical evidence for a $\gamma$-ray emission halo
surrounding the Galaxy. Maps of the emission are derived. EGRET data were
analyzed in a wavelet-based non-parametric hypothesis testing framework, using
a model of expected diffuse (Galactic + isotropic) emission as a null
hypothesis. The results show a statistically significant large scale halo
surrounding the center of the Milky Way as seen from Earth. The halo flux at
high latitudes is somewhat smaller than the isotropic gamma-ray flux at the
same energy, though of the same order (O(10^(-7)--10^(-6)) ph/cm^2/s/sr above 1
GeV).
