  Recent Milagro observations of the Cygnus region have revealed both diffuse
TeV gamma-ray emission and a bright and extended TeV source, MGRO J2019+37,
which seems to lack an obvious counterpart at other wavelengths. Additional
study of this curious object also promises to provide important clues
concerning one of the Milky Way's most active environments. We point out some
of the principal facts involved by following three modes of attack. First, to
gain insight into this mysterious source, we consider its relation to known
objects in both the Cygnus region and the rest of the Galaxy. Second, we find
that a simple hadronic model can easily accommodate Milagro's flux measurement
(which is at a single energy), as well as other existing observations spanning
nearly seven orders of magnitude in gamma-ray energy. Third, since a hadronic
gamma-ray spectrum necessitates an accompanying TeV neutrino flux, we show that
IceCube observations may provide the first direct evidence of a Galactic
cosmic-ray accelerator.

Astrophysics;High Energy Physics - Phenomenology;Nuclear Theory