Surface displacement data from earthquakes are essential for characterizing the fault slip distribution with depth. The Hebgen Lake earthquake was a large normal event with a geometrically complex surface rupture, which broke across mountainous terrain. This study takes advantage of high-resolution historical stereo-imagery to measure the vertical and horizontal displacement from correlation of the orthorectified pre- and post-earthquake image mosaics. The results reveal new strike-slip surface ruptures which are possibly associated with the aftershocks from 18\textsuperscript{th} August 1959. The kinematic role of these structures is likely related to the accommodation of internal deformation induced by the mainshock strain field. Additionally, the comparison of our results with the existing displacement data shows that the OIC-derived offsets often exceed the field measurements by $>$50\%. We attribute this difference to the inelastic damage accommodated off the main rupture.