  We present deep continuum observations using the GISMO camera at a wavelength
of 2 mm centered on the Hubble Deep Field (HDF) in the GOODS-N field. These are
the first deep field observations ever obtained at this wavelength. The 1 sigma
sensitivity in the innermost approx. 4 arcminutes of the 7 utes map is approx.
135 uJy/beam, a factor of three higher in flux/beam sensitivity than the
deepest available SCUBA 850 um observations, and almost a factor of four higher
in flux / beam sensitivity than the combined MAMBO/AzTEC 1.2 mm observations of
this region. Our source extraction algorithm identifies 12 sources directly,
and another 3 through correlation with known sources at 1.2 mm and 850 um. Five
of the directly detected GISMO sources have counterparts in the MAMBO/AzTEC
catalog, and four of those also have SCUBA counterparts. HDF850.1, one of the
first blank-field detected submillimeter galaxies, is now detected at 2 mm. The
median redshift of all sources with counterparts of known redshifts is med(z) =
2.91 +/- 0.94. Statistically, the detections are most likely real for 5 of the
seven 2 mm sources without shorter wavelength counterparts, while the
probability for none of them being real is negligible.
