NGC 2174 is an H II emission nebula located in the upper portion of Orion - near the Hunter's head and close to the constellation of Gemini - and is associated with the open star cluster NGC 2175. It was discovered in 1877 by Jean Marie Stephan, and is thought to be located about 6400 light-years away from earth.

NGC 2174/5 has several apparently detached clusters formed by hierarchical collapse, and it now envelops a number of young and bright stars, such as the blue star in the center of the image. The nebula's glow results from the excitation of atoms by the intense visible and ultraviolet radiation from the stars within - note the dark portion on the bottom side of the cloud where the glowing gas is being hidden by a dense cloud of interstellar dust.