  The region around SGR 1806-20 and its host stellar cluster Cl* 1806-20 is a
potentially important site of particle acceleration. The soft $\gamma-$ray
repeater and Cl* 1806-20, which also contains several very massive stars
including a luminous blue variable hypergiant LBV 1806-20, are capable of
depositing a large amount of energy to the surroundings. Using the data taken
with the \emph{Fermi} Large Area Telescope (LAT), we identified an extended LAT
source to the south-west of Cl* 1806-20. The centroid of the 1-50~GeV emission
is consistent with that of HESS J1808-204 (until now unidentified). The LAT
spectrum is best-fit by a broken power-law with the break energy
$E_\mathrm{b}=297\pm15$ MeV. The index above $E_\mathrm{b}$ is $2.60\pm0.04$,
and is consistent with the flux and spectral index above 100 GeV for HESS
J1808-204, suggesting an association between the two sources. Meanwhile, the
interacting supernova remnant SNR G9.7-0.0 is also a potential contributor to
the LAT flux. A tentative flux enhancement at the MeV band during a 45-day
interval (2011 Jan 21 - 2011 Mar 7) is also reported. We discuss possible
origins of the extended LAT source in the context of both leptonic and hadronic
scenarios.
