  I review recent results on the spatial distribution of substructure in CDM
halos. I show that the spatial distribution of subhalos is anisotropic and
generally prolate with a long axis that is closely aligned with the long axis
of the total mass distribution of the host halo. I show that the correlation
between the subhalo distribution and the long axis of the host halo is strong
both in dissipationless and dissipational gasdynamical simulations. More
massive subhalos tend to be more strongly clustered along the major axis of the
host halo reflecting filamentary accretion. The anisotropy of subhalos has
potential implications for the interpretation of several observations in the
Local Group and beyond. For example, I show that while the mean projected mass
fraction in substructure in the central regions of CDM halos is fsub \approx
0.4%, fsub is a strong function of projection angle and is ~ 5 to 6 times
higher for projections that are nearly collinear with the major axis of the
host halo.
