  The region around the $\eta$ Car nebula has three OB associations, which
contain a Wolf-Rayet star and several massive O3 stars. An early Chandra ACIS-I
image was centered on $\eta$ Car and includes Trumpler 16 and part of Trumpler
14. The Chandra image confirms the well-known result that O and very early B
stars are X-ray sources with L$_X$ $\simeq$ 10$^{-7} \times$ L$_{bol}$ over an
X-ray luminosity range of about 100. Two new anomalously strong X-ray sources
have been found among the hot star population, Tr 16-244, a heavily-reddened O3
I star, and Tr 16-22, a heavily-reddened O8.5 V star. Two stars have an
unusually large L$_X$/L$_{bol}$: HD 93162, a Wolf-Rayet star (and possible
binary), and Tr 16-22, a possible colliding wind binary In addition, a
population of sources associated with cool stars is detected. In the
color-magnitude diagram, these X-ray sources sit above the sequence of field
stars in the Carina arm. The OB stars are on average more X-ray luminous than
the cool star X-ray sources. X-ray sources among A stars have similar X-ray
luminosities to cooler stars, and may be due to cooler companions. Upper limits
are presented for B stars which are not detected in X-rays. These upper limits
are also the upper limits for any cool companions which the hot stars may have.
Hardness ratios are presented for the most luminous sources in bands 0.5 to 0.9
keV, 0.9 to 1.5 keV, and 1.5 to 2.04 kev. The available information on the
binary nature of the hot stars is discussed, but binarity does not correlate
with X-ray strength in a simple way.
