  This paper investigates the origin of the $\gamma$-ray emission from MGRO
J1908+06 in the GeV-TeV energy band. By analyzing the data collected by {\it
Fermi}--LAT, VERITAS, and HAWC, with the addition of spectral data previously
reported by LHAASO, a multiwavelength (MW) study of the morphological and
spectral features of MGRO J1908+06 provides insight into the origin of the
$\gamma$-ray emission. The mechanism behind the bright TeV emission is studied
by constraining the magnetic field strength, the source age and the distance
through detailed broadband modeling. Both spectral shape and energy-dependent
morphology support the scenario that inverse-Compton (IC) emission of an
evolved pulsar wind nebula (PWN) associated with PSR J1907+0602 is responsible
for the MGRO J1908+06 $\gamma$-ray emission with a best-fit true age of
$T=22\pm 9$ kyr and a magnetic field of $B=5.4 \pm 0.8\ \mu\mathrm{G}$,
assuming the distance to the pulsar $d_{\mathrm{PSR}}=3.2$ kpc.
