  The Trifid Nebula, a young star-forming HII region, was observed for 16 hours
by the Chandra X-ray Observatory. We detected 304 X-ray sources, thirty percent
of which are hard sources and seventy percent of of which have near-infrared
counterparts. Chandra resolved the HD164492 multiple system into a number of
discrete X-ray sources. X-ray emission is detected from components HD164492A
(an O7.5III star which ionizes the nebula), B and C (a B6V star), and possibly
D (a Be star). HD164492A has a soft spectrum (kT ~ 0.5 keV) while the component
C blend shows much harder emission (kT ~ 6 keV). The soft spectrum of the O
star is similar to emission seen from other single O stars and is probably
produced by shocks within its massive stellar wind. Lack of hard emission
suggests that neither a magnetically confined wind shock nor colliding wind
emission is important in HD164492A. A dozen stars are found to have flares in
the field and most of them are pre-main sequence stars (PMS). Six sources with
flares have both optical and 2MASS counterparts. These counterparts are not
embedded and thus it is likely that these sources are in a later stage of PMS
evolution, possibly Class II or III. Two flare sources did not have any
near-IR, optical, or radio counterparts. We suggest these X-ray flare stars are
in an early pre-main sequence stage (Class I or earlier). We also detected
X-ray sources apparently associated with two massive star forming cores, TC1
and TC4. The spectra of these sources show high extinction and X-ray
luminosities of 2 - 5 x 10^{31} erg/s. If these sources are Class 0 objects, it
is unclear if their X-ray emission is due to solar-type magnetic activities as
in Class I objects, or some other mechanism.
