The initial dynamical states of star clusters and associations provide useful
insights into the star-formation process. Recently, there has been rapid
advancement in studies of these systems using the precision astrometry
from the European Space Agency's Gaia mission, which provides a window
into stellar kinematics at the sub-km/s level. In this talk I will discuss
the stellar content of nearby star-forming regions, identified via
multi-wavelength observations, and the kinematics of these systems.
From a sample of ~30 nearby star-forming regions, we found the populations
of young stars to be dynamically hot, and most systems to be in a state
of rapid expansion. I will highlight results from the North America
Nebula, where we have pieced together a full six-dimensional kinematic
picture of the system using both Gaia measurements of stars and molecular
line observations of the cloud. This system is comprised of multiple
groups of stars, each rapidly expanding, that are associated with
different parts of the molecular cloud. Stellar ages appear similar
to the free-fall time of the cloud, suggesting that star-formation
occurred rapidly. We also note that star formation is simultaneously
occurring in widely separated regions of the cloud for which the
sound crossing time is much larger than the stellar ages – a difficult
to explain phenomenon that is frequently encountered. Finally, the
expansion of groups appears tied to the observed disruption of the
cloud from massive star feedback. I will evaluate the observed properties
of this and other regions in light of competing theoretical frameworks for
star formation.