Abstract
The Head of Orion is a complex star forming region which includes a young open cluster (Collinder 69, about 5 Myr), two dark clouds (Barnard 30 and Barnard 35, with younger populations) and other younger areas (LDN1588 and LDN1603). We have observed one square degree in each of these regions with Spitzer in order to study the stellar and substellar population. These data have been complemented with optical and near infrared photometry and spectroscopy. We have studied the Class I and II relative population and tried to understand it in the context of the differences in the local environment and the evolution.
