  We present wide-field Halpha images of the Galactic supernova remnant
G156.2+5.7 which reveal the presence of considerable faint Halpha line emission
coincident with the remnant's X-ray emission. The outermost Halpha emission
consists largely of long and thin (unresolved), smoothly curved filaments of
Balmer-dominated emission presumably associated with the remnant's forward
shock front. Patches of brighter Halpha emission along the western,
south-central, and northeastern regions appear to be radiative shocked ISM
filaments like those commonly seen in supernova remnants, with relatively
strong [O I] 6300,6364 and [S II] 6716,6731 line emissions.
  Comparison of the observed Halpha emission with the ROSAT PSPC X-ray image of
G156.2+5.7 shows that the thin Balmer-dominated filaments lie along the
outermost edge of the remnant's detected X-ray emission. Brighter radiative
emission features are not coincident with the remnant's brightest X-ray or
radio regions. Areas of sharply weaker X-ray flux seen in the ROSAT image of
G156.2+5.7 appear spatially coincident with dense interstellar clouds visible
on optical and IRAS 60 and 100 micron emission images, as well as maps of
increased optical extinction. This suggests significant X-ray absorption in
these regions due to foreground interstellar dust, especially along the western
and southern limbs. The close projected proximity and alignment of the
remnant's brighter, radiative filaments with several of these interstellar
clouds and dust lanes hint at a possible physically interaction between the
G156.2+5.7 remnant and these interstellar clouds and may indicate a smaller
distance to the remnant than previously estimated.
