  We present a study on the gamma-ray emission detected by the AGILE-GRID from
the region of the SNR G78.2+2.1 (Gamma Cygni). In order to investigate the
possible presence of gamma rays associated with the SNR below 1 GeV, it is
necessary to analyze the gamma-ray radiation underlying the strong emission
from the pulsar PSR J2021+4026, which totally dominates the field. An
"off-pulse" analysis has been carried out, by considering only the emission
related to the pulsar off-pulse phase of the AGILE-GRID light curve. We found
that the resulting off-pulsed emission in the region of the SNR - detected by
the AGILE-GRID above 400 MeV - partially overlaps the radio shell boundary. By
analyzing the averaged emission on the whole angular extent of the SNR, we
found that a lepton-dominated double population scenario can account for the
radio and gamma-ray emission from the source. In particular, the MeV-GeV
averaged emission can be explained mostly by Bremsstrahlung processes in a high
density medium, whereas the GeV-TeV radiation by both Bremsstrahlung (E < 250
GeV) and inverse Compton processes (E > 250 GeV) in a lower density medium.
