  We present a multi-wavelength study of the young stellar population in the
Cygnus-X DR15 region. We studied young stars forming or recently formed at and
around the tip of a prominent molecular pillar and an infrared dark cloud.
Using a combination of ground based near-infrared, space based infrared and
X-ray data, we constructed a point source catalog from which we identified 226
young stellar sources, which we classified into evolutionary classes. We
studied their spatial distribution across the molecular gas structures and
identified several groups possibly belonging to distinct young star clusters.
We obtained samples of these groups and constructed K-band luminosity functions
that we compared with those of artificial clusters, allowing us to make first
order estimates of the mean ages and age spreads of the groups. We used a
$^{13}$CO(1-0) map to investigate the gas kinematics at the prominent gaseous
envelope of the central cluster in DR15, and we infer that the removal of this
envelope is relatively slow compared to other cluster regions, in which gas
dispersal timescale could be similar or shorter than the circumstellar disk
dissipation timescale. The presence of other groups with slightly older ages,
associated with much less prominent gaseous structures may imply that the
evolution of young clusters in this part of the complex proceeds in periods
that last 3 to 5 Myr, perhaps after a slow dissipation of their dense molecular
cloud birthplaces.
