We present the first∼ 7 farcm 5� 11 farcm 5 velocity-resolved (∼ 0.2 km s− 1) map of the [C ii] 158 μm line toward the Orion molecular cloud 1 (OMC 1) taken with the Herschel/HIFI instrument. In combination with far-IR (FIR) photometric images and velocity-resolved maps of the H41α hydrogen recombination and CO J= 2–1 lines, this data set provides an unprecedented view of the intricate small-scale kinematics of the ionized/photodissociation region (PDR)/molecular gas interfaces and of the radiative feedback from massive stars. The main contribution to the [C ii] luminosity (∼ 85%) is from the extended, FUV-illuminated face of the cloud (G 0> 500, 5� 10 3 cm− 3) and from dense PDRs (10 4, 10 5 cm− 3) at the interface between OMC 1 and the H ii region surrounding the Trapezium cluster. Around∼ 15% of the [C ii] emission arises from a different gas component without a CO counterpart. The [C ii] excitation, PDR gas turbulence, line opacity (from [13 C ii]), and role of the geometry of the illuminating stars with respect to the cloud are investigated. We construct maps of the L [C ii]/ and / ratios and show that L [C ii]/ decreases from the extended cloud component (∼ 10− 2–10− 3) to the more opaque star-forming cores (∼ 1010− 4). The lowest values are reminiscent of the"[C ii] deficit" seen in local ultraluminous IR galaxies hosting vigorous star formation. Spatial correlation analysis shows that the decreasing L [C ii]/ ratio correlates better with the column density of dust through the molecular cloud than with /. We conclude that the [C ii]-emitting column relative to the total dust column along each line of sight is responsible for the observed L [C ii]/ variations through the cloud.