  We measure the distance to the supernova remnant G15.4+0.1 which is likely
associated with TeV source HESS J1818-154. We build the neutral hydrogen (HI)
absorption and 13CO spectra to supernova remnant G15.4+0.1 by employing the
data from the Southern Galactic Plane Survey (SGPS) and the HI/OH/Recombination
line survey (THOR). The maximum absorption velocity of about 140 km/s
constrains its lower limit distance of about 8.0 kpc. Further, the fact that
the HI emission feature at about 95 km/s seems no corresponding absorption
suggests that G15.4+0.1 has likely an upper limit distance of about 10.5 kpc.
13CO spectrum to the remnant supports our measurement. The new distance revises
parameters on its associated pulsar wind nebula and TeV source.
