Recent neutral hydrogen (HI) 21 cm line surveys of the Galactic plane, have allowed exploring the interstellar medium in more detail. In particular, HI absorption spectra allow kinematic distances to be determined for strong radio continuum sources such as supernova remnants (SNRs). Additionally, Galactic plane surveys in the CO line allow measuring molecular clouds and their kinematic distances. We concentrate our studies on supernova remnants that have been discovered to be $gamma$-ray emitters by high energy instruments, including space missions such as Fermi and Cerenkov air shower experiments like H.E.S.S.