  We present a panoramic map of the entire Milky Way halo north of dec~-30
degrees (~30,000 deg^2), constructed by applying the matched-filter technique
to the Pan-STARRS1 3Pi Survey dataset. Using single-epoch photometry reaching
to g~22, we are sensitive to stellar substructures with heliocentric distances
between 3.5 and ~35 kpc. We recover almost all previously-reported streams in
this volume and demonstrate that several of these are significantly more
extended than earlier datasets have indicated. In addition, we also report five
new candidate stellar streams. One of these features appears significantly
broader and more luminous than the others and is likely the remnant of a dwarf
galaxy. The other four streams are consistent with a globular cluster origin,
and three of these are rather short in projection (<10 degrees), suggesting
that streams like Ophiuchus may not be that rare. Finally, a significant number
of more marginal substructures are also revealed by our analysis; many of these
features can also be discerned in matched-filter maps produced by other authors
from SDSS data, and hence they are very likely to be genuine. However, the
extant 3Pi data is currently too shallow to determine their properties or
produce convincing CMDs. The global view of the Milky Way provided by
Pan-STARRS1 provides further evidence for the important role of both globular
cluster disruption and dwarf galaxy accretion in building the Milky Way's
stellar halo.
