We present first results from an X-ray study of the Hubble Deep Field North
(HDF-N) and its environs obtained using 166 ks of data collected by the Ad
vanced CCD Imaging Spectrometer (ACIS) on board the Chandra X-Ray Observato
ry. This is the deepest X-ray observation ever reported, and in the HDF-N i
tself we detect six X-ray sources down to a 0.5-8 keV flux limit of approxi
mate to 4 x 10(-16) ergs cm(-2) s(-1). Comparing these sources with objects
seen in multiwavelength HDF-N studies shows positional coincidences with t
he extremely red object NICMOS J123651.74 +/- 621221.4, an active galactic
nucleus (AGN), three elliptical galaxies, and one nearby spiral galaxy. The
X-ray emission from the ellipticals is consistent with that expected from
a hot interstellar medium, and the spiral galaxy emission may arise from a
"super-Eddington" X-ray binary or ultraluminous supernova remnant. Four of
the X-ray sources have been detected at radio wavelengths. We also place X-
ray upper limits on AGN candidates found in the HDF-N, and we present the t
ightest constraints yet on X-ray emission from the SCUBA submillimeter sour
ce population. None of the 10 high-significance submillimeter sources repor
ted in the HDF-N and its vicinity is detected with the Chandra ACIS. These
sources appear to be dominated by star formation or have AGNs with Compton-
thick tori and little circumnuclear X-ray scattering.